Probably generic or overarching categories are good. Getting too specific will have less broad appeal and people can always search for more specific hashtags if they want. #photography #music #art #artstr #fitness #health #bookstr are examples of broad topics that many people might be interested in. #plebchain #introductions #grownostr are also good as gathering places for a mashup of topics and people.
Discussion
Agreed. It also may be worth having a landing page of some sort for new accounts describing some that aren’t obvious knowledge (like your examples of plebchain, etc) and others. I find there’s much less # use here than on IG or twitter so directing to common ones that can lead to greater connection would be good