Well some corys prefer slightly lower temps than that (like peppered corys), and some can tolerate higher temps up to 28-30 (like sterbai corys) - 24 is a good average though, and you could keep bronze, albino, panda (all readily available) or go for a more unusual type. Perhaps find some websites devoted to corys and see what types take your fancy and then come back for a second opinion on them.