Generally speaking usenet indexers are not specialized so most of the time you'll just have to try different general usenet indexers & see if any work out for you.

for general

Most usenet indexers are in that category. If you are just starting out then look into NZBGeek & expand from there. Their internal forums can also help with learning about the rest of usenet.

music

Same as above, most people use general usenet indexers. The only specialized indexer is the Headphones VIP indexer, not sure if it's worthwhile but you can try it yourself https://headphones.codeshy.com/vip/

anime

Anime Tosho specializes in that category (they aren't just strictly usenet). Otherwise it's general usenet indexers.

and/or pro wrestling content?

Doesn't exist, you'd need to use general usenet indexers.