In that case I suggest going with https://mayfirst.coop/ or https://riseup.net/ if what you want to do fits their profile (struggle for freedom, grassroots democracy, co-operatives, equality, environment, against imperialism, against capitalism, against fascism (f.ex. Trump), etc.).

If what you want to do doesn't fit that profile at least somewhat, https://hcoop.net/ might be more your thing.