Alongside the various !city/province/state communities I know some have been working to get going, and given the trend of posts lately, I came across a few broader focus communities for civilian activity that may be worth a look.

!organize@lemmy.world
!movement@lemmy.world
!protest@lemmy.world

Another more recent community that brought this to mind was for local organizing:
!act_local@lemm.ee

Whether one wants to contribute to the first few or use them as a model to make their own communities elsewhere is neither here nor there to me, but I think the basic ideas may be solid. Having distributed communities for sharing organizing resources and helping direct people to existing groups to join and coordinate with would be of great use.