Godot Game Engine
godotengine.org
godotengine.org
Happy to answer any questions about Godot!
[0] https://docs.godotengine.org/en/stable/tutorials/networking/... [1] https://docs.godotengine.org/en/stable/classes/class_multipl... [2] https://docs.godotengine.org/en/stable/classes/class_multipl... [3] https://github.com/cridenour/GodotSteam
Right now if you don't want to build it, you have to hope someone is offering it for free - where in Unity there are many options for almost anything you can think of varying quality/price.
It's just such a game changer for prototyping or just being new to game dev.
You can look through this list for games that have the little "playable in browser" badge, but that doesn't appear to be a search filter option. You can also remove the open source tag from the filter to get more results.
Here are direct links to some examples
https://alzter-s.itch.io/supertux-classic
Edit: see the comment from sxx, they found the right filter. There is a "platform" field that can be set to web, separate from the tags.