My all-time favorite comic is "Death Vigil." It's only like 12 issues. I don't think he'll be making any more, but it was sooo good. It's essentially about a cult trying to unleash demons on the world and they want to take the Reaper's job while they're at it. The Reaper is female, and she is awesome. Very powerful, but very sweet.

I also really love Pathfinder. It really just exists to promote the tabletop game...but it's still a wonderful fantasy series and has a canon lesbian couple.

And I can't recommend the Jem and the Holograms comics highly enough. They're loosely based on the 80s cartoon (which is very adult and, believe me, withstands the test of time - check it out!) and about rival all-girl rock groups. Unfortunately the series ended; the main artist went on to other projects and they got Meredith McClaren to take over, and her art was so bad it killed the franchise. The characters went from looking glamorous to basically muppets. T_T But that's only in the later issues, starting around #19 or so. There's also a canon lesbian couple in Jem. In the cartoon, one girl from each of the rival bands quits her group because she feels underappreciated, and instead they form a duo. It was only one episode of the cartoon but fans really enjoyed it and they became a popular femmeslash pairing, so in the comic reboot the creators just made the couple canon!