Relatively Cheap Odd Paladin

Generally, with this deck, the above six cards are all decent if you can mulligan for them. I'll point out one or two of them that I (personally) find really good against certain matchups.

Lost in the jungle is good for early tempo.

Stonehill Defender lets you get another taunt minion and even makes people wary of a potential Tarim.

Benevolent Djinn is just a clutch heal card that's saved my butt more than once.

Boisterous Bard helps keep minions on the board early.

Unidentified Maul just gives a good buff pretty much every time. Yes, it is luck based, but there is no buff that is particularly bad.

Elven Archer helps prevent a pesky minion from surviving with 1 health. I find it useful in the early game. NOTE: do not just use it to go face on turn one, it can really mess you up sometimes.

Against Aggro, I generally find it useful to have early pressure that my opponent has trouble getting rid of. 

The Lost in the Jungle lets you get two minions out of turn one, and they can be really threatening if not dealt with.

The Boisterous Bard can keep your minions on the field for longer so you have something to deal with their board.

The Stonehill Defender gives you a relatively early taunt, and can provide you with a second taunt on top of it.

Odd Paladin is a relatively fast deck, but it doesn't rush too much, meaning you can afford to play a slower game. 

Lost in the Jungle is still good here, for the same reason as always: early pressure.

Unidentified Maul may seem a bit strange, but it lets you buff your minions and gives you a weapon to remove enemy minions with.

Level Up! is not usually a good mulligan early, but if you're playing control and the game is slower, it's still viable and it's a solid card to have by turn five, ready to go. Quick tip: try to use level up if there are at least 4 Silver Hand Recruits on your board. It's just more value and honestly, with Odd Paladin, it's not too difficult to do either.