The crocs shoes with the most notable function is probably the Golden Loki horn. However, it's not always easy to find one, especially if you don't want to splurge. Some sellers on eBay sell their own versions of this horn. Also, a few retailers offer Loki themed Crocs. Unfortunately, these aren't sold by Crocs itself, but you can get them from retailers that carry the Crocs brand. If you don't like eBay, you can search for a seller on Etsy that offers this horn.
cheerios Crocs
These Crocs shoes are not cheap, but they are fun and functional. With a slew of different colors, you can find one that suits your needs.