All steeds will use the warhorse statblock. With each locomotion, its ability will change. Trample for 60 feet, Grappling Claws for climb speed, Amphibious for swim speed. After you choose your creature's locomotion, choose a taxonomic class to place your steed in and the type of damage it deals (Bludgeoning, Piercing, Slashing). Once that has been done, send a short description and image of the mount if possible. Place your discord name and once it has been finished and submitted, a DM will tell you if you are approved.

Trample: If the steed moves at least 20 ft. straight toward a creature and then hits it with a natural weapon attack on the same turn, that target must succeed on a DC 14 Strength saving throw or be knocked prone. If the target is prone, the steed can make another attack with its natural weapon against it as a bonus action.

Grappling Claws: If the steed hits with an attack, it can use a Bonus Action to attempt to Grapple the target creature with an escape DC of 14.

Amphibious: The steed can breathe air and water