Wire.

End-to-end encrypted collaboration platform by Wire Swiss GmbH (Zug, Switzerland)

Facts

BigBlueButton (self-host)
Virtual classroom and video conferencing; self-hostable
EU · open-source
↗
CryptPad
End-to-end encrypted collaboration (FR/EU).
FR · open-source
↗
Nextcloud Deck
Kanban board app for project management within Nextcloud
DE · open-source
↗
Flock
Team messaging and collaboration platform with EU data centres
NL · commercial
↗
FluffyChat
Open-source Matrix chat client with focus on simplicity and privacy
DE · open-source
↗
HedgeDoc
Markdown collaboration; self-host.
DE · open-source
↗
Huly
Open-source project management and team collaboration platform
PT · open-source
↗
HumHub
German open-source social intranet and collaboration platform
DE · open-source
↗