Light Cavalier

The following features do not apply if the player is wearing medium or heavy armor.
The following features only apply to mounted movement/combat.

Horse Archery

If you normally impose disadvantage on ranged attacks (including spells) made while mounted, this disadvantage no longer applies.
Alternately you gain advantage on ranged attack rolls against an enemy that is 20-60ft away.

Master Lancer

While wielding a Lance you gain the following features:

• Ignore disadvantage on attack rolls for targets within 5ft.
• +2 to AC against melee weapons.

Expert Rider

You have advantage on saving throws made to avoid falling off your mount. If you fall off your mount and descend no more than 10 feet, you can land on your feet if you’re not incapacitated.

You have proficiency with Animal Handling for any rolls that apply to mounted movement/combat.
Double proficiency with Animal Handling if you already have it.

If your mount gets spooked/scared you can ease the mount as a reaction with a DC12 Animal Handling roll.

Finally, mounting or dismounting a creature costs you only 5 feet of movement, rather than half your speed.