AO3, fanlore, they publish an academic journal, lots of legal work, some preservation of old archives and shit.

I don't even like OTW (I like some of their projects but not the whole org overall) but they do a lot of stuff and it makes sense they'd have a big budget. Frankly I think they should stop relying on an all-volunteer base to run their stuff and hire a CEO with more experience running nonprofits. It'd be worth boosting up their budget for that expense.