Leprd: Free web hosting for hobbyists! Seems like a genuine free webhost.
Marigold Town: Free web hosting for hobbyist, personal, artistic, and/or otherwise non-commercial websites with the theme of that every website is a plot of land in a town.
Haza: Free(?) Dobrado (CMS) webhost with support for many IndieWeb protocols! Nevertheless it looks empty. Not trying to insult the webhost, it just what it feels like to me.
Lexi's Hosting: Another free webhost, though it has PHP support, and free webmail.
Buruma Hosting: A fairly obscure webhost that if you want to register, you have to email them. Currently open as of writing this.
Colorful-Life: A game of life implementation in full color, fun to mess around with.
DroneWorld: I really don't know what is this, but you can fly around I guess.
webXash: An improved version of Xash3D-empscripten, you can play Half-Life on the browser using this site!
OpenLara: Open-source engine of classic Tomb Raider Series, it's crossplatform but you can also play it in the browser.
Katawa Shoujo: Re-Engineered: A modernization of the classic visual novel Katawa Shoujo, with accessibility features that you can play even in the browser!
Baba Is Wons: Someone remade the majority of Baba Is You levels in their web version of the game, check it out!
Game Engines
Bitsy: A little browser-based engine for little games, worlds, and stories.
Bipsi: A tool to small lo-fi games to play in the browser. Inspired by and an imitation of the Bitsy game maker.