Here are a few more discoveries. Eth's Skin is set in a beautiful magical version of the Pacific coast of British Columbia, and features a quiet, androgynous fisherperson, a currently-grumpy-and-snarky selkie, a mermaid, some beachwalkers (including a lesbian couple with children), and a floating raft town. Lovely, simple black and white line drawings.
For contrast, two comics by Aero Zero with intense gorgeous colors and very striking character designs (especially the monsters) and landscapes. She describes Kyria as a "light-hearted epic fantasy" and Men+Monsters as "a romantic fantasy adventure about a teratophile knight, his monster lover, and their robot companion" - that one has m/m smut. (You can elect to view the explicit or the less-graphic version.)
And yet another contrast, the elegant Curia Regis, political machinations (neither gay nor magical) among the nobility in someplace like 18th - 19th century France. That one is complex and I have decided to buy the books so I can more easily flip back and forth to follow the hints and sort out what's up. It starts out in striking black and white, and later becomes color - sort of a flat, stylized look.
And then for you fans of comic-book style super-heroes who'd like to see some gay guys among them, there's The Young Protectors.
Except for TJ and Amal, which is complete, these are all on-going stories. You'll need to go back to the beginning to get caught up, which could keep you busy for awhile! They update once or twice a week.
Does anyone know any good webcomics with lesbians? I should at least link here to the archives of Dykes to Watch Out For, for anyone who wants a cultural history lesson of American lesbian-feminism beginning in the 80's and '90's, from Alison Bechdel (who gave us what's come to be called the "Bechdel test" in that very cartoon).
ETA: There's also this beautifully color-penciled story of "a queer 13 year old girl who finds herself stranded in a dangerous place: an all-white Christian youth backpacking camp", As the Crow Flies.