Photo Editing
inkscape (alternative to Adobe Illustrator)
https://inkscape.org/
https://gitlab.com/inkscape/inkscape
GIMP (alternative to Photoshop)
https://www.gimp.org/
https://github.com/GNOME/gimp
Video Editing
OpenShot
https://www.openshot.org/
https://github.com/OpenShot/openshot-qt
Media Player
VLC
https://www.videolan.org/vlc/
https://github.com/videolan
Social Media
Funkwhale (alternative to Spotify, Deezer...)
https://funkwhale.audio/
https://github.com/ellisist/funkwhale
Hubzilla
https://hubzilla.org/
https://github.com/HaakonME/hubzilla
Browser Extensions
SimpleTranslate (alternative to Google Translate)
https://addons.mozilla.org/firefox/addon/simple-translate/
https://addons.mozilla.org/firefox/addon/simple-translate/privacy/
https://chrome.google.com/webstore/detail/simple-translate/ibplnjkanclpjokhdolnendpplpjiace
Dark Reader
https://darkreader.org/
Libredirect [hot (very)]
A web extension that redirects YouTube, Twitter, Instagram... requests to alternative privacy friendly frontends and backends.
https://libredirect.github.io/
Firefox: https://addons.mozilla.org/firefox/addon/libredirect/
Edge: https://microsoftedge.microsoft.com/addons/detail/libredirect/aodffkeankebfonljgbcfbbaljopcpdb
Chromium: https://github.com/libredirect/libredirect/blob/master/chromium.md
Alternative-Front-Ends
Wikipedia --> Wikiless
https://wikiless.org/
https://codeberg.org/orenom/wikiless
Youtube --> LibreTube (Android Only) built with Piped
https://github.com/libre-tube/LibreTube
Get it on f-droid: https://f-droid.org/en/packages/com.github.libretube/
Get it on GitHub: https://github.com/libre-tube/LibreTube/releases/latest
Youtube --> Yattee Alternative YouTube frontend for iOS, tvOS and macOS built with Invidious and Piped
https://github.com/yattee/yattee
Spotify --> Soju
https://github.com/coffeebank/soju
https://playsoju.netlify.app/
Office Application
OpenOffice
https://www.openoffice.org/
https://github.com/apache/openoffice
OTHERS
https://fediverse.party --
https://searchengine.party -- Web page for comparing popular search engines across some privacy-centric data points
https://privacytests.org -- Open-source tests of web browser privacy.