From Homestar Runner to Salad fingers to badgers, stick figure battles, and the End of Ze World, this — dare I call it an artform? — was a cultural touchstone for a generation.
Flash made vector animation available to the masses, and internet distribution of the relatively small video files was a piece of cake. With the filetype now essentially deprecated, the creators gone on to bigger and better things, the distribution sites shut down, it is a dead form. Most of it will be lost forever, although there may be someone archiving some of it for posterity.
There are in-browser emulators written in JavaScript. Like any old content, I’m more worried about sources going down rather than not being able to run the flash.
The biggest one (also adopted by the wayback machine) is actually written in Rust (compiled to WASM).