You obviously want to choose a tribe based on something that you have a passion in. We highly recommend you choose a niche/topic that is closely related to your blog to make it as easy to target and invite potentially interested users. Due to the vast and virtually limitless amount of niches and interests out there, there are tons of great tribe names still available. Here are some examples of general tribe ideas:
Interests tribe (ex: /t/gardening, /t/books, /t/entrepreneurship, /t/birds, /t/diy, etc.):
A tribe focused mainly on a general interest. This is the most popular tribe type as there are nearly endless amounts of topics and interests out there, especially in all the smaller niches.