D&D 5E What are some optimal combos for 2 lvl 4 PCs as mount and rider?

[EnWorld#0000]

My buddy and I are making new PCs to play in the Out of the Abyss setting (in the Underdark), with new level 4 PCs. I'm thinking of playing a Moon Druid to wildshape into a mount, and my buddy would play the rider. What are some amazing combos of races/feats/classes? We can draw from the WotC books, with UA being subject to DM's approval, with standard point buys for abilities.

I'll definitely start wildshaping into a Giant Spider, because we're teamed up with 2 Gloom Stalker Rangers, and we need the darkness.

 

[mellored]

Mounted combat for the rider. Heavily armored, focusing attacks on him. Halfling (small to ride medium mounts) paladin would be really good at level 6. They could also get away with taking the speed penalty of low Str in heavy armor, since they aren't walking themselves.

Sentinel for the mount. Get's a free attack each time the enemy attacks the rider. Wolf is good for prone, as is larger mounts, to give your ally advantage. You can also polymorph yourself at level 5, though you lose sentinel.

 

[CTurbo]

I agree with mellored completely. Halfling Paladin with Mounted Combat riding a Wolf with Sentinel is just mean. Mounted Combat allows you to force attacks against your mount to be towards you instead which would trigger Sentinel every round. The Wolf would get advantage on all attacks when mounted. Both of you would always be in your Aura of Protection. It's hard to see your mount ever taking any damage. You'd probably want to expend all healing on yourself since you'd be taking most of the damage.

 

[Blue]

Halfling who rides on the back of Goliath yelling out "Who runs Bartertown!" is always classic.

On a more serious note, hands are useful things for druids, plus I've loved this picture for a while: