The blue fang and its relatives, out of the Guianas and northern Brazil. Biologically odd in a way that matters: these are the tarantulas with urticating hairs on the pedipalps rather than the abdomen, so the flicking motion is entirely different and they can deploy while facing you.
They are fossorial as juveniles, building silk-lined burrows with a turret at the entrance, and become more surface-active with age. E. cyanognathus has the metallic blue chelicerae the genus is named for, though the color is far more subtle in person than in photos.
Never abundant. Breeding is inconsistent, sac sizes are modest, and imports from French Guiana are irregular, which keeps prices well above what the size and difficulty would suggest. Availability moves in waves.