https://game-icons.net/ is absolutely fabulous! I've been using these icons constantly and it helps a lot with the "programmer art" of my current game. If you need icons, do check them out.
Had not seen this site before, but looks cool. I typically just use OpenClipart (largely because everything is CC0, I do not like being required to attribute even though I usually do anyway) for this sort of stock art, but more options are always nice.
I used also openclipart but this site has way better and more importantly, consistent quality