Just tried the Cobalt Violet from Blue Ridge Artist Materials. It’s nice. It has a high pigment load. On their website they say that their paint maker—Eric Silver—learned paint-making from Robert Doak. His paint handles similarly to his—not at all stiff, but rather smooth and creamy.
Like Doak, they grind their paint in a linseed/walnut blend in (they say) small batches. The prices are pretty reasonable and they have a nice (if not extremely broad) range of single-pigment paints. They have some interesting historical colors such as genuine vermilion, rose madder, and lead tin yellow. They also offer a copal medium and a copal retouch varnish.
If you are a reader and you have experience with these guys and their products, I’d be obliged if you’d share it in comments.