Great question. There doesn't seem to be a platform specific concept similar to "Certified Employee Owned" [1], but you might consider getting in touch with Certified EO to see if they would develop one.

I too would be interested in using only non-exploitive platforms, bonus if it cuts the legs out from underneath the traditional VC funded platforms.

[1] https://www.certifiedeo.com/eo/about

They could make a directory. If a ZTaxi user opens the app in an unserved city, the app should recommend similar apps that serve the city. Cut out the search engine middle man.

One way is to do a google search for ".coop", which turns up a ton of cooperative organizations.