I'm curious to hear other's thoughts on they think would be useful.
Please don't hold back ideas! There's very little harm positing silly or unlikely ideas, but there is some potential value (perhaps more than you realize).
Inspired in part by calebo's comment here
Fiscal sponsorship can be very helpful for new groups!
Though regarding attorney fees:
Where are you getting this from? Attorney fees are on the order of $2-5k.
https://nonprofitelite.com/how-much-will-it-cost-to-get-501c3-tax-exempt-2/
The following two firms used to post public quotes on the order of $2-3k in 2018 (it seems they've taken down the public quotes):
https://www.501c3.org/501c3-services/start-a-501c3-nonprofit/
https://www.harborcompliance.com/nonprofit
Starting a non-profit includes non-trivial amounts of other kinds of work though.