What types of pointe shoes are best for extremely flexible feet.?

Something with a high vamp and strong box, and maybe a more flexible sole. You could try cutting a tiny chunk (like a quarter of an inch) out of the outer sole right where it bends when you are en pointe to help the shoe conform to the shape of your foot better. You must do this in just the right spot for your foot and shoes, though, otherwise it will be a problem rather than a help. Dont worry, this isnt just some bogus trick, people use it professionally.