Videoconfencing:

• Jitsi is free, open source, and you don't need to download anything -- it just works in the web browser. You can use their public instance for free.
• May First is hosting a Jitsi instance.
• The Free Software Foundation is hosting a Jitsi instance for use that FSF members can use to start and host calls.
• I found out about BigBlueButton, which optimizes for teaching/learning/webinars/workshops. Via the tech-coop mailing list: there's a new Online Meeting Cooperative in case you want to use a cooperatively maintained BigBlueButton instance!

Currently I use a mix of Jitsi, Whereby, Uberconference, Google Meet, Zoom, Signal, and probably something else I am forgetting. I aim to move as many of those as possible toward free services and away from proprietary ones.

Document editing and sharing:

I wrote to the tech-coop list talking about what I need in a Google Docs replacement, thus kicking off a thread where a few people recommended various NextCloud arrangements. I found out that a Dutch host named The Good Cloud is offering "its services, including the privacy-friendly Nextcloud Talk, free for 3 months for all companies, organizations, government institutions), schools and organizations." Currently I use a mix of Etherpad, GitHub, Google Docs, GitLab, Dropbox Paper, HackMD, and probably three other things I'm forgetting. Again, I aim to move as many of those as possible toward free services and away from proprietary ones. At some point soon I should probably get a Nextcloud instance, either paying someone else (preferred) or doing it myself, and see how it does for this sort of thing.

(Followup to a related post in March.)

Edited the same day to add:

Oh yeah, another few things I had in my open tabs:

Sourcehut: "Git and Mercurial hosting, mailing lists, bug tracking, continuous integration, and more".

Several projects at switching.software.

Collective Tools is one of the co-ops offering Nextcloud hosting and support -- as well as Rocket.Chat and Deck (a kanban board application).