>>6317220As in, the ones who sculpt and sell the dolls, or the ones who customize them and offer their skills?
If it's the first one, you really should read the guides. The 2.0 (linked at the end of the recap) answers pretty much anything you need to know; it's long but after reading it a lot of stuff will be more clear.
The second, that's a little more difficult.
Flickr, Tumblr, Instagram and forums are the best place to find other collectors and thus artists too.
Sadly the good ones often don't offer commissions or are constantly booked.
>>6317223I have a very set image of the characters I want to "shell", so I usually just look/wait for a doll that I can think can be customized the best to fit that envisioned look.
If you are not the type for, hm, imagination without a guide, I can highly recommend those mentioned doll maker games other anon linked.
Else look on Flickr and co. for other BJD pictures for inspiration, or human ones too.