If you want something simple you can always just use songs/specific singers as voice claims. I often use Spotify and just try to find lesser known artists and basing the type of voice your looking for by the genre of music. Or, if you comsume alot of media, you can search up interviews or clips of celebrities/tv shows/movies or anything like that. Interviews are pretty good if youre looking for a full vocal of the person you find fits your character’s voice the most. Or video games work too!
If youre looking for unique voice claims, and are willing to pay for actual voice actors, ive seen alot of ppl use twitter! For other websites, ive heard alot of people suggest Voices and Voquent! Though like i said, its a hire and pay service.