Nitor - a discord clone with a shared/federated Identity layer, but self-hosted "servers/guilds". Trust model is to trust the guild server (e.g., so private channels work as one would expect with moderation capabilities), but to enable E2E DMs and friend/presence systems via guild servers as relays. Rust, Iced, Iroh.

Glyphcraft - a Minecraft mod (imagine if Thaumcraft, Ars Nouveau, and Hex Casting were smashed together)