Housemaids were hurrying homewards with their purchases for various Gallic breakfasts, and the long sticks of bread, a yard or two in length, carried under their arms, made an odd impression upon me.
– Louis Charles Elson (1898)
It is going to be interesting to see if/when they move to opencloud (from open-xchange) where they have greater control of the feature-set and bug fixes as they are both part of Heinlein Gruppe.
Either way I am happy with them so far, while also having some minor annoyances (syncing of shared task list on iOS is a bit weird, and no IMAP VTODO (combined calendar and tasks)).
I tried making my own, but generally I download them from Ankiweb. It depends on the deck how well build they are and which media they contain (audio/images/weblinks).
Anki?
FOSS and you can create your own decks or download those made by others.
While US citizens pay for the tariffs, it may well hurt producers of imported goods.