@Lumeinshin @sneeden

If you are talking about ads bringing people to your instance, I'd probably try telegram.
Ads and the platform you're gonna put them on are directly related to the people you want to attract.

There are differences even between gay fedi and dark fedi. People around these parts wouldn't tolerate banner ads and would probably change instance/client. On the other hand you could just add the ad to your profile and/or pay popular account to add it to their profiles. I'd think influencer type marketing would work.