The North American natives. Thirty-plus described species scattered across the American Southwest and down into Central America, and they share a personality: slow, terrestrial, drab by tarantula standards, and almost impossible to kill. A. chalcodes and A. hentzi are the two most keepers meet first.
The slowness is not a minor trait, it is the defining economic fact of the genus. A sling can take five to eight years to reach adult size, longer than almost anything else in the hobby. That is why the price curve here is so lopsided: slings are among the least expensive tarantulas you can buy, and a confirmed adult female represents most of a decade of somebody's time. Wild-collected mature males occasionally flood in from Arizona and Texas during monsoon season, which briefly craters prices on a few species every summer.