Other than the pally skill of former editions? I cannot say tbh, but you can most easily create such a thing yourself :
Rein of steed summoning:
Once per long rest you can use this rein to summon a medium warhorse for 8 hours. The warhorse is a perfect exemplar of its kind and comes completely with bridle. does not need water nor nourishment and seems to be summoned directly out of the beastlands. It never requires any riding check during normal movement.
Just attach the rein to the headstall and mount up.
If the horse is killed during its duty, it does not die, but is instead returned to the beastlands. It vanishes after 8 hours of duty, the rider gets some haptic signals, by three short pulls on the reigns, one round before this happens, so he can safely dismount.
In the first Critical Role campaign the party's ranger had a magical necklace that could be used to place her animal companion into an extradimensional space for safekeeping, and summon him back out as needed. I don't know if it was ever written up in either of the two Exandria sourcebooks (Tal'dorei Campaign Setting and Explorer's Guide to Wildemount).