Llamas?
Ostards?
Nightmares?
I seem to recall that if you didn't have a minimum skill set than you couldn't have the animal traded to you, but that may have been a UO:R ruleset.
Nevermind. Wiki comes through with my answer

Thanks Pirul, even better than the Wiki answer as you provided tipsPirul wrote:There are no minimal skill requirement to mount or own. You cannot have frenzied ostards or nightmares transferred to you unless you do have a minimum skill (I ignore the exact number), but you can retame them with 0 skill.
What some people do is have a tamer put the mount on follow mode, and then friend the person who'll be riding it, and that seems to work just fine. The person can even refresh it simply by hopping off and back on.