After cliches of art photography, why not have cliches of photojournalism/documentary photography. There's a bit of crossover here between all the categories but you get the idea.
Most of the cliches are so huge in their range of possible treatments that they are only cliches if they are treated in a cliched manner. When someone says "Homelessness has been done", he or she is hugely wrong. Nothing has "been done". For all its ubiquity, photography has scraped the surface of all the categories listed here or elsewhere. Stick a half-original treatment in there and you find a fresh perspective on something that has supposedly been done a million times before.
Anyway, cliches of photojournalism, off the top of my flu-addled head, in no particular order.
Illness & Disease
Housing and homelessness
Exotic and not-so-exotic minorities
Any more categories (All sport, especially boxing and amputee football, is banned). I'm having trouble coming up with the Documentary Photograph Ever, though. Any suggestions?