the big ones out there are BigBlueButton and Jitsi. they have a lot of public instances, so you can easily check if they fit your needs.
das ändert sich dann im Informatik Studium;)
every provider who supports aliases. like foo+baa@bzz.tld where everything after the + is exchangeable. so you can use a 'different' mail for every service you use and just block where spam comes from via the alias.
Damm i read ABP ... and was confused. Yeh sure ads are smoll brain! (Same as ABP)
ADS?
Matrix i guess, its a federated messaging protocoll. Flagship messenger app would be Element. Sending large files would depend on the server you are on.
Has a mobile app!
I use it daily for travel by bike or foot (kombined with BRouter). And its awsome!
Experiance by car is a bit mixed tho. (EU-Germany)
I lost THE GAME
Maybe have a look at the tool from 0&0 called "shut up windows 10"
Russian moon probe crashed into ... the moon.
Godwin survives everything, he likes to live very cramped and sometimes enjoys bad hair day.
I only know German ones: senfcall.de or bbb.digitalcourage.de