How did you choose the relays you have? Did you just start adding miscellaneous relays? Are relays just relays or do some of them have personalities (in a sense?)
Discussion
You can say that I choose them to maximize coverage, these are popular relays.
If you want relays by topic, the only one I know is the one that nostr:npub1995y964wmxl94crx3ksfley24szjr390skdd237ex9z7ttp5c9lqld8vtf launched today.
If you want to browse nostr by topic, try looking for hashtags that interest you.
There is something called communities also which is the nostr version of subreddits, you might want to look into that (see the website satellite.earth)
nostr:note1csr56crs0ssz8zcu8yghdmvaxerd5pkwegqad3qemmd2ucu0urdqxlwv56