There’s also a list of plenty of other fantasy consoles, some that are FOSS and web-friendly: https://github.com/paladin-t/fantasy
Ironically, I wouldn’t be surprised if some consistent subset of Flash or Shockwave would actually be a fair option, as most of the security complaints about Flash were mainly for it being too privileged and having unsafe methods of browser integration (and ‘trusting’ Adobe to solely steward all this). Whereas running Flash stuff in Ruffle, within a webpage (not with any extended privileges in a browser plugin or desktop app) really wouldn’t be too controversial.
There are actually still some funded competitions on Newgrounds of still producing Flash content yet, even in like 2022 or so.