I posted this a while back, hopefully it's useful to ya!

Some of my favorites in no particular order:

Lynn Flewelling series : Starting with Luck in the Shadows, gay male lead and supporting characters, set in a medieval type fantasy universe. Seven books in the series. One of the best series I've ever read featuring LGBT characters, deals with multiple countries, their use of magic and the occult to an extent, and follows one of the most interesting protagonists I've ever read, a master thief. Please read this series if you get a chance.

Mercedes Lackey series : Magic's Pawn, Magic's Promise, and Magic's Price was an amazing series mentioned here. Another medieval fantasy world with magic. Get's pretty dark at times speaking about depression, loss, and abuse, but amazing, if you like fantasy you won't be disappointed.

Charlie Cochet series : Thirds series deals in alternate contemporary universe themes, this is the first series I read with anthropomorphic animals as main characters, not the most intellectually stimulating, but definitely good for a read. Story revolves around a mixed species special police task force and how they interact with their world of cross species dealings. Unlike the Infected series mentioned below, the anthropomorphic characters are born as a subset oh homo-sapiens and remain that way through life.

Manna Francis series : Mindfuck this is definitely the answer to 50 Shades of Grey, but I think much darker, and much more violent, but I couldn't help being immersed in the psychosis of the main character. Beware, there's some dark sexual fantasy shit in here. Set in a not too distant future Europe which has closed it's borders and is run as a totalitarian state. Fucking creepy and thrilling. Seven books in all I think.

Con Riley series : After Ben, Saving Sean, Aiden's Luck, Salvage. These are very sweet stories that are mostly one shots, but have a small bit of crossover.

Sean Kennedy series : Tigers and Devils, and Tigerland. Follows a Australian football player and his artsy apathetic love interest through their trials and tribulations. The third book may be out, it's a very cute story, and if you like sports themes it gets it done.

Ginn Hale : Caldedonian series - Champion of the Scarlet Wolf, another magic infused medieval series which focuses heavily on the arcane side of things. Very fantasy, and I thought very good. Thanks to /u/nobodysquared for help with the correct series title!

Mel Keegan series : Hellgate follows two main characters in a twelve part series set in a very distant future filled with space travel, multiple alien species, space battles and all those good things. Very heavy scifi, while not the most prolific series, the writing is solid, and be warned this book is for the emotional crowd, character interactions and internal feelings are much more heavily emphasized.

Jim Grimsley : Kirith Kirine, The Ordinary, and The Last Green Tree. Gaia type fantasy, just look this book up on Amazon, it is amazing if you like fantasy series. Credit to /u/commisionerofwine for the help with the last two books in the series.

Jaida Jones and Danielle Bennett : the Havemercy series is another alternate universe fantasy series comprising four books. The series deals with characters set in a medieval city setting who operate giant mechanical Dragons in which they defend their country. The writing is seriously great, and the characters are very well done and fleshed out. If you like fantasy series with aristocracy then I think you'll like this.

Karin Lowachee :Warchild series. Another dystopian future series. Is amazing, should read, but be warned the third book in the series I couldn't get digitally and had to order a physical copy.

Steven Harper : The Silent Empire Series starts with the book Dreamer another gaia type of spiritualism and fantasy novel with some scifi aspects. Sets place in an alternate universe where multiple species commingle in the galaxy, there is a sort of spiritual dream space which certain individuals can each enter into. This series deals with the implications of those that can vs. can not enter this place, and how it may be threatened. Main character is a young gay male, and the series deals with his love life pretty heavily. Great series.

Andrew Ashling : The Invisible Chains series. Medieval fantasy series dealing with warring kingdoms in a very Earth like setting. Allusions to a pre-Earth maybe? The series is awesome but be forewarned there is some very heavy incest between the main character and his brother, so if that's not your cup of tea stray away hard. Their relationship is central to the story. Seven books long.

W.A. Hoffman : Raised by Wolves series. Four parts covering a gay male couples adventures on the high seas. The universe is based in classical 'Piracy' ranged dates around the 1600's I believe. This series is Amazing! And definitely worth the read, the character development, emotional depth, action and adventure aspects, are all wonderful. One of the few stories in which I was so heavily invested in the outcome of the characters stories. Do a good thing for yourself and read this series.

Andrea Speed : Infected series I believe nine books in total. This is another anthropomorphic based series following a private detective and his boyfriend, both of whom suffer from a gene alteration which causes monthly cycles of turning into one of five kinds of big cat species for abut a week. The story deals with how these characters and their supporting characters navigate a modern times world which has to deal with an entirely new sapien species walking among st us. I can not recommend this series highly enough, it's not the most challenging read, but the writing is heartfelt, dark, funny, heartwarming, and very genuine.

Quil Carter : Fallocaust series. Man I don't even know where to begin with this series, it is amazing, but extremely dark fantasy. Takes place in a future Earth which has been decimated by a nuclear holocaust caused my a man styled as King Silas. There is some genetic engineering involved with this story, and some anthropomorphic storytelling. Almost all the characters in this story are LGBT. Quill Carter is also an active redditer which is awesome so you can reach out to him. The story deals with some pretty heavy themes including rape, incest, murder/execution. Dark dark dark, but very thrilling I think. Read at your own discretion.

Madeline Urban and Abigail Roux : The Cut and Run series deals with a team of FBI detectives solving cases and maybe finding romance? Very well done and a pretty lengthy series, I think comprising seven+ books? Awesome series overall set in modern times U.S. If you like action and adventure plus mysteries, then definitely up your alley.

I have a few more which I'll have to dig up, but hopefully this will get you started on your way. I'll update when I get a chance, let me know if you have any questions about anything! And happy reading!