Images of colubrid snakes. The family colubridae encompasses roughly two thirds of all extant snakes. Although some species are closely related, colubridae has become a catch-all garbage family for all snake species that do not fit elsewhere in the order. Colubrids are generally non-venomous. Some well-known groups include garter snakes, grass snakes, rat snakes, boomslangs (exceptionally venomous), smooth snakes, whip snakes, milk snakes, vine snakes and racers.