Donate to the ones you use. Maybe Lemmy.

maybe PeerTube (or Framasoft in general)

There’s also lots of organisations/projects to donate to on https://opencollective.com/discover?show=open+source

Aside from Lemmy, how about any good Linux distro? Honestly, a tremendous amount of work goes into those and they serve as a springboard to everything else FOSS. Donate to them!

How about FreeBSD?

grapheneOS! also whonix

OpenBSD Foundation: https://www.openbsdfoundation.org/donations.html

Akira Ux