I just read the whole comic available today and I spotted something. Didn't really see this anywhere but sorry if it's already been told.
I noticed that in the 469th panel, when they're in the diner I believe, there are characters that resemble Maggie from Ava's Demon (right) and Ace from Colorless (middle-left) which are both webcomics too. Maybe there are more references I don't spot cause I don't know the shows/comics. What do you think?