Ghost knight

The Order of Knights Incorporeal, or Ghost Knights,
arose in the principalities of Morgau and Doresh. Fighters
who follow the Ghost Knight archetype draw power from
undeath and bring themselves closer to that grim fate in
service to their vampiric and ghoulish masters.
BONUS PROFICIENCY
Beginning when you choose this archetype at 3rd level, you
gain proficiency in the Animal Handling skill.
PALE RIDER
Also at 3rd level, you can cast find steed. The steed created
is an undead creature that takes the form of a ghostly pale
or dappled riding horse. Your GM can substitute a camel,
a mastiff, or another mount appropriate to your character.
When you reach 7th level, a ghostly, undead warhorse
becomes available.
You can cast this spell once, and regain the ability to do so
when you finish a long rest. While riding your mount, you
can use a bonus action to have the steed make one attack.