Client SEO - What Niches do you go for?

Hi guys,
when reaching out to new potential SEO-Clients, which niches do you mostly target? I usually just choose niches, where I guess the potential client would be able and willing to pay 1k+/month for my services. Are there any other things or specific niches I could look for?

Local offline professionals like dentists and lawyers. They're competitive businesses so they need an edge. Plus they have lots of money.

Casinos, Betting Providers + Affiliates in the gambling Industry. Al lot of competition and they have a lot to spend.