Excalidraw

Collaborative whiteboard
Alternative to: Figma
Firefish

Decentralised social network
Alternative to: Twitter
Gitea

Git service
Alternative to: GitHub
Invidious

YouTube frontend
Alternative to: YouTube
Jitsi Meet

Video conferencing
Alternative to: Zoom, Microsoft Teams
Lemmy

Social link aggregator
Alternative to: Reddit
LibreQR

Web interface for generating QR codes
LibreTranslate

Translation API
Alternative to: Google Translate
Lufi (member-only)

File uploading and sharing
Alternative to: WeTransfer
Matrix (member-only)

Instance messaging server
Alternative to: Slack, WhatsApp
Miniflux (member-only)

RSS feed reader
Alternative to: Feedly, Inoreader
mygpo (member-only)

Manage and sync podcast subscriptions
Alternative to: Spotify, Apple Podcasts
Nextcloud (member-only)

Online storage, filesharing platform
Alternative to: Dropbox, Google Drive
Nitter

Twitter frontend
Alternative to: Twitter
Petrolette

News reader
Alternative to: Feedreader
PrivateBin

Secure pasting service
Alternative to: Pastebin
SearXNG

Internet metasearch engine
Alternative to: Google, Bing
Send (member-only)

Send encrypted files
Alternative to: Dropsecure, WeTransfer
Teddit

Reddit frontend
Alternative to: Reddit
Transfer.sh (member-only)

file sharing via the command line