Alex,
Yep....Canon's own MR-14EX or a cheaper option is the Sigma EM-140 DG.
If you go for a Sigma, it must be specified for a Canon camera as they make different versions for different manufacturers but they all have the same model number.
The final option is technically not a ringflash...the Canon MT-24EX. It's a twin lite that mounts around the end of the lens in a similar manner to a true ringflash.
Bob