These are my top 10 favorite ongoing series (as of May 2019).
There are lots of great limited series that come and go but I'm trying to focus here on books that I can count on to entertain me month-in and month-out. It takes a special creative team to keep up a solid book for a "long haul" (something in comics nowadays that is longer than 6 months). There are fewer and fewer long-form storytelling series every year as things move to "tell a story arc and restart. I generally don't consider a series for the Top 10 until it's at least 3-4 issues into a run. I don't want to imply that it's easy to do a single GREAT issue, but it's much harder to keep it up over the course of several months. Details on how my Top 10 has changed and why can be found below.
There are other comics I really enjoy, but that come out too infrequently, have recently ended, or (as mentioned above) are too new. You can see all the comics I'm currently reading on my Pull List page.
As with anything: Your Mileage May Vary
These are my favorites and everyone is going to like different things...
These are creators who I think turn out top notch work and I follow them wherever they go and whatever they do:
Neil Gaiman (writer): I've loved his work since I read his early work on Miracleman (following Alan Moore) from Eclipse and his opus from DC/Vertigo, Sandman. I've read his prose and loved it all. There are currently a number of comic book adaptations of his prose novels and short stories available, primarily from Dark Horse Comics, including his epic American Gods.
Los Bros Hernandez (writers/artists): Brothers Gilbert & Jaime Hernandez have been telling wonderful slice of life (with various fantastical elements sometimes mixed in) in Love & Rockets since 1981. They are pioneers of independent creator-owned comics and I'll pick up anything they do, their work has been collected in a number of formats and is fairly easy to find.
Terry Moore (writer/artist): From his masterwork Strangers in Paradise to Echo, Rachel Rising, and Motor Girl, I will read anything Moore puts out. He returned to SiP in2018, putting out 10 issues of Strangers in Paradise XXV. and is currently following that up with a crossover of all the characters in the "Terryverse" called Five Years.
Stan Sakai (writer/artist): While it does not come out strictly monthly and may have large gaps in publication, I will always pick up his masterwork Usagi Yojimbo whenever an issue is published. Don't be fooled by the 'funny animals', this is a meticulously researched historical drama set in the Edo era of Japan. Stan recently moved Usagi to IDW from it's long time publisher Dark Horse.
Brian K. Vaughan (writer): Best known for Y: The Last Man, Ex Machina, Runaways, Saga, The Private Eye, and, most recently, Paper Girls. I'll try pretty much anything he writes.
I really need to modify this more often, it seems to be mostly an annual update!
May 2019 - A perennial favorite of mine, Saga by Brian K Vaughan & Fiona Staples, is on a 1-year hiatus so it dropped off. I added on a series I have loved for many years, Knights of the Dinner Table by Jolly Blackburn, which although it has undeniably crude art, the stories have always spoken to the role-playing gamer in me and it's always one of the first comics I read whenever I receive it. Marvel/DC books tend to drift on and off my list depending on the current creative team. The Immortal Hulk is a really solid, but darker, take on the character by Al Ewing, and Mark Waid is really entertaining me with his recent Doctor Strange in space stories. When I heard Waid was doing this take on the character I was suspicious, but he has really pulled it off and entertains me each month. Criminal is an extremely entertaining hard-boiled crime "series of series" by Ed Brubaker & Sean Phillips, while Ascender is the fantasy continuation of the sci-fi series Descender by Jeff Lemire & Dustin Nguyen. I also added on the creator-owned series Brian Michael Bendis & Micael Gaydos started when Bendis moved to DC called Pearl, which I've been enjoying. Amazing Spider-Man dropped off with the most recent artist change, the Unbeatable Squirrel Girl is still a great book, but it got knocked down somewhere in the 11-20 range.
Aug 2018 - Another year and a lot of my favorites ended or transformed, I'm also moving from a Top 12 to a Top 10. Too many books that I like do not sustain themselves over the long haul. Harrow County ended this year, but I highly recommend the 32 issue run. Astro City also came to a close as a comic series and will continue on with occasional Original Graphic Novels. Invincible Iron Man with Riri Williams ended, Tony Stark is back in the Iron Man suit and the new Ironheart series starring Riri from a new creative team has not debuted yet. Black Hammer is an example, for me, where a little bit of something is great and when I get too much I like it less. I still like it, but with multiple spin-off series over the last year it has been diluted for me and fallen out of my Top 12. Batman lost its Top 12 luster for me with the non-event of Batman & Catwoman's aborted wedding in #50. But, there are always comics titles that will step in for me and fill the spots vacated by fallen comrades. Paper Girls by Brian K. Vaughan & Cliff Chiang charges onto the list at spot #3, David Lapham's crime epic Stray Bullets moves up to #4, and The Unbeatable Squirrel Girl moves up a spot to #5. Saga just went on a 1 year hiatus, but it will be back so I'm going to leave it up on the list, but it slips down to #6 due to the hiatus and the fact I won't be reading any new Saga stories for the next year. Amazing Spider-Man just finished up a long run by Dan Slott (that I mostly enjoyed) and has been taken over now by Nick Spencer & Ryan Ottley (artist on the fabulous Robert Kirkman super-hero book, Invincible). I'm really enjoying this book, but I have a soft spot for Spidey, this debuts on the Top 10 at #7. Rick Remender's Deadly Class debuts at #8, this is a book that may get a lot of attention when its series debuts on SyFy (the trailer I saw looked pretty good). Manifest Destiny, the supernatural explorations of Lewis & Clark in an alternate version of the American frontier, remains in my top 10 and is at #9. Rounding out my Image Comics dominated Top 10 (7 of the 10) is Monstress, by Marjorie Liu with gorgeous art by Sana Takeda.
Aug 2017 - Another round of changes that just goes to show that things change over time. Infrequent production has dropped a couple of great series from the list since last time... Southern Bastards has not had a new issue since January 2017, and Lazarus has had only 1 issue since last time, in March 2016, with a spinoff Lazarus X+66 taking its place that itself only had a single issue in July. Amazing Spider-Man dropped off due to a common Marvel illness: crossover-itis, as it was pulled into the Secret Empire event which I am not enjoying. Wonder Woman dropped off when Greg Rucka ended his run as writer with issue #25. Scarlet Witch ended after a 15 issue run in April 2017 and Clean Room ended with issue 18 in June 2017, both are excellent series to check out in collected editions. That will move my 6 ongoing favorites that stuck around up into the top slots, with the college hijinks of Giant Days taking the #1 position from the grim zombie apocalypse drama of Walking Dead. Saga, Harrow County, Astro City, and The Unbeatable Squirrel Girl round out the top 6, leaving room for some newcomers to the list. Tony Stark's replacement, Riri Williams, starring as Ironheart in The Invincible Iron Man charges onto the list in spot #7, followed closely by my favorite Brian Michael Bendis creation, Jessica Jones. Next up is David Lapham's crime noir series Stray Bullets: Sunshine & Roses, I've been reading this series in one incarnation or another since 1995 and it continues to deliver a gritty realistic story, brutal or unsettling at times but always a good read. Another series I have been enjoying is Manifest Destiny, an alternate history version of Lewis & Clark's explorations into the unexplored west of the North American continent...if they found all kinds of fantastic and supernatural things along the way. I'm also enjoying Jeff Lemire's Black Hammer, his deconstruction of the superhero genre in the wake of an apocalyptic event. My final entry is a surprise to me: after declaring Tom King's Batman #1 to be one of my least favorite Batman stories of all time (an opinion I still hold), I tried Batman again with "The Button" crossover, which was OK, but the following issue, #23's 'The Brave and the Mold' team-up with Swamp Thing was an awesome read. This was followed by a great story with Catwoman, focusing on Bruce & Selina's relationship and then launched into 'The War of Jokes and Riddles' where I can really see Tom King hitting his stride and getting a good handle on the character of Batman, a take that I'm fully on board with.
Nov 2016 - A lot of change in the past year. Two series that were in my Top 12 a year ago have ended their runs: Rachel Rising (what a great series, I highly recommend getting the collected editions), Rebels (seemed too short, but ended after a 10 issue run, I suspect most comic readers don't enjoy historical fiction as much as I do). Shutter is dropping off, only 6 issues came out in the last year and the story is not grabbing me as much as it did in the early days. Black Magick had a strong start, but hasn't had an issue out since Feb 2016. Greg Rucka & Nicola Scott are likely too busy on DC's rebooted Wonder Woman series, but that has moved onto the Top 12 taking Black Magick's spot. Elephantmen has only had 5 issues published in the last year, and 3 of them didn't really grab me, so that has been edged out of the Top 12 for now. Ed Brubaker's Velvet seems to have gone dormant, nothing in the past 6 months, and Brubaker is working on other stuff right now, so that one has dropped off. Ms. Marvel, that used to tell quite charming stories focusing on Kamala Khan, has gotten too involved in crossovers and other characters from the MarvelU, so that has dropped off the list. So that is 7 books off the list, with 5 holding onto the Top throughout 2016: Walking Dead (holding at #1, Kirkman continues to entertain and surprise me), Saga, Lazarus, Astro City, and Clean Room. Moving onto the list: Giant Days (I really love this comedic comic chronicling the lives and loves of British college kids), Amazing Spider-Man (back on top after an absence of several years, I'm loving Dan Slott's "Peter Parker as International CEO" storyline while it lasts, and I'm really loving the current Clone Conspiracy story), Harrow County (a wonderfully creepy story that I jumped onto late and immediately collected every back issue), Southern Bastards (a multiple award winning comic, for good reason), Scarlet Witch (James Robinson knocked it out of the park with the mostly "done in one" stories over the title's 1st year), Unbeatable Squirrel Girl (this one is just fun, I love the little asides Ryan North puts at the bottom of every page), and Wonder Woman (this is my favorite of the DC Rebirth titles, Greg Rucka is doing a great job writing and switching context between parallel stories so each story can have a consistent art team on the bi-weekly schedule of the book).
Nov 2015 - Alex+Ada ended (and it was a great wrap-up) so that dropped off the list. Afterlife with Archie is published to infrequently to hold onto its spot on the Top 12, so it will move down to the honorable mention list. Gotham Academy dropped out of favor for me with the inclusion of Damian Wayne, I liked it as a bit more separate from the rest of the DCU. Coffin Hill was either cancelled or went on hiatus, no new issues being solicited. Rebels has an extremely strong debut and has been holding the quality for 7 issues. Black Magick and Clean Room both wowed me with their debut issues. Elephantmen moved back into my Top 12.
Dec 2014 - Alex+Ada continues to wow me and has moved up to the #1 spot, displacing Saga's long-standing grip on the top spot. Infrequent publication has pushed Elephantmen and Rai off my Top 12. I still love both series, but other stories I follow have taken over the higher spots. The ever excellent Afterlife with Archie has jumped onto the Top 12, as well as the excellent Gotham Academythat really impressed me with the first few issues. X-O Manowar, a favorite for a long time has dropped off due to being pulled into far too many crossover events which, in my opinion, prevented the title from shining on its own. This opened up some space for Ed Brubaker's excellent spy thriller Velvet to jump onto the Top 12.
Nov 2014 - A couple of titles have broken into the Top 12 to replace books that have slipped out, mostly due to the series ending (Harbinger, Hawkeye, Sergio Aragonés Funnies, Eternal Warrior) or an inconsistent publication schedule (Great Pacific). Lazarus has just gotten better & better and has jumped from #8 to #4. X-O Manowar jumped from #11 to #7 based on it's strength as the linch-pin title for the Valiant Universe. Alex+Ada has been superb and debuts at #3, knocking Rachel Rising down to slot #5 (Rachel is still a thoroughly enjoyable title even though it dropped a couple of slots). All the series that ended opened up space for Shutter, Ms. Marvel, Rai, Coffin Hill, and Astro City to join the Top 12. One thing I've noticed is that I seem to like a lot of series with female leads (Lazarus, Rachel Rising, Shutter, Ms. Marvel, and Coffin Hill)
Dec 2013 - Top books have to really click for me on the writing AND the art. Harbinger moves down 3 slots to Rank #4 due to inconsistent art, though I love the story. Replacing Harbinger at #1 is Saga, moving up 4 slots, a stupendous combination of Brian K Vaughn's writing & Fiona Staples' art. Walking Dead and Rachel Rising swapped places (Walking Dead moving up to Rank #2 and Rachel dropping to Rank #3). Archer & Armstrong, previously on the list at Rank #4 dropped off entirely due to a combination of inconsistent art and a couple of story arcs that didn't click with me as strongly as the 1st arc out of the gate. On the strength of a fabulous arc starting at #51 coming in right after another solid arc, Elephantmen rose 2 to Rank #5. Hawkeye held firm at Rank #6 and Sergio Aragonés Funnies rose 3 to Rank #7. Lazarus, a brilliant newcomer debuted at Rank #8, displacing New Avengers that dropped off the list entirely due to it's lengthy participation in the muddled Infinity crossover. Eternal Warrior and Mind MGMTdebuted on the Top 12 at Ranks #9 and #10. Rounding out the Top 12, X-O Manowar dropped 2 slots to Rank #11 due to an art change that was not my favorite and Great Pacific held onto Rank #12. The Massive lost some momentum with me and slipped off the list from it's previous position at Rank #11.
Sept 2013 - World's Finest drops out of the Top 12, replaced by Great Pacific. No more DC in the top 12... Rachel Rising & Saga both raised up a few notches, Rachel is now at #2. Joshua Dysart, Terry Moore is knocking at your door!
Aug 2013 - Deathmatch & Thor drop out of the Top 12, replaced by Sergio Aragonés Funnies & The Massive.
Apr 2013 - Converted the top 10 to the top 12.
Thor & World's Finest drop out of the top 10 (but is still in the top 12), art team shuffling around on both titles have caused them to suffer, IMO. Hawkeye & New Avengers both jumped into the Top 10, both have been impressing me on story & art.
Jan 2013 - Daredevil drops out of the top 10 (but is still in my top 20). I'm not loving the current dynamic between Matt & Foggy. Replaced in Top 10 with the outstanding debut of Deathmatch from Boom! Studios.
Dec 2012 - Amazing Spider-Man drops off the list when Peter Parker is "Killed" (temporarily, I'm sure) in ASM #700, replaced in Top 10 with Thor: God of Thunder (Editorial note: They did eventually bring Peter Parker back after a couple of years in pretty much the exact way I thought they would...)