Some friends and I just started a tool library in Central Oregon: https://cotool.org/
There some quite generous community donations of tools (not money) to get started. Startup costs were small, and now a couple weeks after opening we have dozens of members.
It scales nicely because we can just buy more or less new tools. It's very impactful to some people, and once started there's very little recurring expenses.
That said, although starting a new organization may not take much money, it does take a lot of wisdom and social capital. I would say that you succeeded at something quite difficult.
When I've sought out volunteer activities in the past, it was usually when my social and personal life were on shaky grounds. In particular, when I was in no shape to start something new the way you did.
I've often heard volunteering recommended as an antidote for loneliness, but as grogenaut observed, this advice can sometimes be tricky to follow in practice.
I'm not a mason, but their motto is "to be one, ask one". You won't see them recruiting, you have to inquire.
I encourage HNers to try it! Just mentally replace "God" with "Nature" and "Jesus" with "Me" in every line and you have a good framework for self-reflection and appreciation of the natural world.
Others who attend church presumably assume that you share the stated beliefs?
Of course there's a fine line between this attitude and being exploited by your employer for free labor. In this case I think it helped that everyone knew it wasn't a career for most of us. You work for a few summers in college and then you graduate and if you want to stay a part of the community you continue volunteering from time to time.
Freemasons: what do they even do? I just know a few secretive fat white guys who belong. They're serious about it. They don't talk about it. Why would I join? I have no idea what they do. Not obviously recruiting in my area.
Boy/Girl scouts: I wasn't able to have a kid and so couldn't volunteer here or sports. It's kinda creepy to do so without a kid. Not obviously recruiting in my area.
YMCA/YWCA: this seems like a straight up company these days. Do they even take volunteers? I don't see any recruiting for it.
Kids who code / other code bootcamps: sent multiple emails. All I got back was marketing asking for donations if I even got that. They did like 2 events a year.
I do volunteer EMS/Fire/Ski Patrol... That requires actual training. Groups were obviously recruiting once I had the skills. They need people to help run large events / medical.