First off, the best of the bunch in my opinion:

http://pandora.xepher.net/daily/20050228.html

It's called Daily Grind, it's very badly drawn in coloured biro, and it looks terrible. However, the dialogue is generally good, and sometimes the story is better than the dialogue.

It's about a do-anything agency run in a world and magic superworld of talking animals (angels are spiders, centipedes are neutral spirits, and demons are I think dead people/animals who were nasty in life).

The main characters are Howlett Creager who's a python size snake, Jolene a near psychotic body building squirrel, Mrs ConstanceTeasdale a stinging moth, Darius Tharka the ex-devil bunny, and a lot of others. Most of the characters are about the same mass despite their approximate species.

Very dark even for adults in places, even though there's no on-screen sex.

The rest in no particular order:

Curvy: http://www.c.urvy.org/

Sexual very often and violent in a cartoonish way, drawn in a Beardslyesqe hippyish style, I am not sure that the story makes sense.

At arm's length: http://atarmslength.smackjeeves.com/comics/

Strange animals with extra arms, which they can hide, can do magic. People/animals without the extra arms can't.

By the Book: http://bythebook.smackjeeves.com/

Some NPCs got hold of a Rulebook, hilarity ensues, or not, depending how you feel about it. Some nudity with obscured bits, but it's pretty blatant what's being obscured.

Retail:http://retailcomic.com/

Jokes about customers and corporate shenanigans.

Banana Triangle:http://www.bananatriangle.com/

Jokes about being shipwrecked.

Jerk City:http://jerkcity.com/

Strange gay/rude comic using speach bubbles on strange (pre-existing?) characters.

Monster Pulse:http://www.monster-pulse.com/

Story about kids having parts removed and made into monsters without the kids dying, and the monsters sort of obey the kids.

Yuusha Hime Kalibourne:http://www.conscrew.com/yuushahime/

Story about a girl with a suit of power armour, probably based on something Japanese I don't understand, but I like it somehow.

"Requiem: An online graphic novel":http://requiem.spiderforest.com/

Sci-fi set on an another world. Sort of looks computer generated, but typically three fairly small images per page, and currently refreshes daily Monday to Friday.

"Requiem: Shadowborn Pariah":http://requiem.thecomicseries.com/

About magic users in a version of our world. Again looks computer generated, or maybe painted and reduced in size, very slow to update, one large image with insets, usually three weeks or more between refreshes.

"Slipstream: Singularity":http://slipstreamsingularity.thecomicseries.com/comics/

Sci-fi from the same people as the second Requiem on my list, same sort of big images, about two weeks between refreshes at the moment, it was in space but the current arc is on a planet, I have no idea how long that will last.