you found..

an archive of like a billion working flash games (and more)

ok its not a billion its more around 100000, but still

bluemaxima's flashpoint is a webgame preservation project, making thousands of old flash games and animations and web games in general playable offiline through a neat launcher

heres something to start with, play the gateway games

bonus: bluemaxima's kahvibreak. same concept just old java 2 micro edition phone games instead

flashpoint kahvibreak