Not OP, but looking at your product works (https://www.cotrain.space/ is neat, BTW!) I think best way to look at other interests is to include those categories which can be followed from youtube easily and can be immediately reproduced such as Painting (imagine group of friends doing Bob Ross paintings), Cooking, Quizzes etc.

Off topic - There seems to be already another product offering similar solution in the name of cotrain.space and the only differentiator in the domain being the hyphen; there will be inevitable transfer of audience with whoever perform better and unnecessary confusion. This guide for naming a Startup/Product I've written can be helpful to you incase you wish to change the name - https://hitstartup.com/how-to-name-our-startup/.