These are all open source Fediverse projects that need help with localisation:
Friendica
https://www.transifex.com/Friendica/friendica/
FunkWhale
https://docs.funkwhale.audio/translators.html
Mastodon
https://weblate.joinmastodon.org/projects/mastodon/
PeerTube
https://github.com/Chocobozzz/PeerTube/blob/develop/support/doc/translation.md
Halcyon (Twitter-like client for Mastodon/Pleroma)
https://translate.zanata.org/project/view/halcyon
Mastalab (Mastodon app)
https://crowdin.com/project/mastalab
Trunk (opt-in people to follow on Fediverse)
https://octodon.social/@kensanata/100986318207250337
Reply if there are others!