McSweeney's Internet Tendency
mcsweeneys.net
Short comic lists and monologues, published daily
Comedy Department
Same six panels every time, different conversation
qwantz.com
Coffee break · Works anywhere
Free, no sign-up · online since 2003
Ryan North has used one identical set of clip-art dinosaur panels since 2003 and changes only the dialogue. T-Rex talks himself into a position, Dromiceiomimus and Utahraptor puncture it, and the argument covers language, ethics or time travel. Constraint does all the work.
Knowing the artwork can never change forces you to read the words properly, which is presumably the entire reason for the format.
Keep going
Picked for a shared category and overlapping vibe, not for popularity.
mcsweeneys.net
Short comic lists and monologues, published daily
theoatmeal.com
Long comic essays about grammar, grief and running
iwastesomuchtime.com
A meme feed built for exactly one idle scroll
smbc-comics.com
Philosophy and biology jokes, with a red button under each
thefarside.com
Gary Larson's cows and scientists, officially online
xkcd.com
Stick figures doing maths, romance and language jokes