I recently read a lot of webcomics and I highly recommend this one:

Masque of the Red Death ( inspired  by Edgar Allan Poe's short story; of course  BL included ^^)

Oglaf (short and kinky stories , very funny, not only BL  ^^)

The Less Than Epic Adventures Of TJ and Amal (main characters are gays)

Starfighter

Teahouse

La Macchina Bellica