Synapse (Matrix homeserver), mautrix-telegram (bridge for Telegram to Matrix), Element Web (Matrix client) Mastodon (federated, activitypub Twitter-like) SyncThing (P2P Dropbox) - fantastic for syncing my purchased music & ebooks between devices and sharing with my wife.

These are all on my small NixOS VPS (or individual devices for SyncThing) - I've been meaning to setup an old laptop as a server at home for home automation and media.