Updated daily (or Mon-Fri)
Everyday Comics
Overcompensating
Shortpacked
Goats
Diesel Sweeties (syndicated)
Sheldon
Dr. McNinja
Dinosaur Comics
Say uncle
Reidsrow
Spare Time Forever
White Ninja

updated about once a week
Riceboy
A Softer World
Horribleville
Cat and Girl
Soylent Brown
Teaching Baby Paranoia
Able and Baker
Joe Loves Crappy Movies
Malfunction Junction
Minus
Not Included
Idiot Comics
stuff sucks
Perry Bible Fellowship
Turtle vs Bunny
Wigu
XKCD

updated rarely
Bang barstal
Blockhead Comics
Ciggaro & Cerveja
Dresden Codak
exploding dog
Her: Girl vs Pig
Isolated Instances of Non-Gravity
Raymondo Person

Never update
A lesson is learned but the damage is irreversible
Copper
9 planets without intelligent life

*Not proven scientifically.