West African arboreals, three species, and H. maculata is effectively the genus as far as the trade is concerned.
Grey and black starburst patterning, extremely fast, and carrying venom significant enough that a bite is a hospital conversation rather than a bad afternoon. They live in tree hollows and will use a cork tube if you give them one.
Here is the thing worth stating plainly: they breed well, and that is what governs what they command. A genuinely dangerous, genuinely fast old world arboreal costs about what a curly hair costs. The price signals nothing about the difficulty, and beginners buy them on cost and appearance more often than any other old world genus.