This site has a list of all of them, look for ones that say "(Working)" after the title.
http://www.wowwiki.com/Mount_macros

Like the following:
Random Smart Mount with Sea Horse, Sea Turtle and Vehicle Exit (WORKING)

#showtooltip Red Proto-Drake
/castrandom [nomounted] Red Proto-Drake, Black Drake
/cast [nomounted] Abyssal Seahorse
/cast [nomounted, swimming] Sea Turtle
/castrandom [nomounted] Brown Riding Camel, Orgrimmar Wolf
/script VehicleExit()
/dismount

For us boxers someone suggested putting
/dismount [mod]
and it will only dismount when holding alt, ctrl, or shift which is useful so you can spam the mount macro in case one of them didnt mount the first time. But that part wasnt working for me.