Dryad Militant
A great turn 1 drop if you don't have an Aether Vial to play. It passively eats away problematic cards that could be reused by things like Snapcaster or Goblin Dark-Dwellers or combo decks that use flashback cards like Storm. It can also trade with Goblin Guide which is usually in decks that you don't want to take too much unnecessary damage from. Also helps keep Tarmogoyf from getting too big.
Anafenza, Kin-Tree Spirit
Anafenza's usefulness is felt more in the early game than as a top-deck later on (unless you have an Eldrazi Displacer on the board already.). She helps beef up your creatures, sometimes getting them out of kill range of Pyroclasm, which can hose this deck. Aether Vial can sometimes allow favourable trades combined with Anafenza that your opponent isn't prepared for.
Thalia, Guardian of Thraben
Thalia is crucial to slowing down your opponent. Death & Taxes generally has a pretty good matchup vs combo decks and combined with Dryad Militant she can make their day miserable. She also helps against Burn decks. Thalia is a lightning rod for removal, so don't expect her to sit on the board for too long and running 4 of her is fine for this reason despite being legendary.
Leonin Arbiter
Oh boy, this guy is one of the cards you're always happy to see in your opening hands. The immense mana pressure it can put on your opponent is only topped by also having a couple of Ghost Quarter in hand to use when they're tapped out. Arbiter is very good in conjunction with Aether Vial to flash in when your opponent tries to fetch.
Blade Splicer
Blade splicer brings all the ground-based pressure you'll need to hold the line while you beat down with your flyers. They'll usually have 2 options: bolt the Golem and risk Splicer being flickered to create more, or bolt the Splicer and have to deal with a 3/3 somehow. Best case scenario you flash in a Restoration Angel or a Flickerwisp via Aether Vial when they target Splicer to really put the opponent behind.
Mangara of Corondor
Mangara while slow is a fairly versatile dude who can exile whichever permanent you want gone. Combine putting his ability on the stack with some sort of flicker effect and he'll dodge his own exile and get to stay around to do it all over again while the opponent loses their permanent to exile. Keep in mind that Mangara can also exile lands. He's pretty dangerous in slower matchups where he can be reused multiple times.
Flickerwisp
With this card the possibilities are (nearly) endless. Flashing it in at instant speed with Aether Vial can protect your board from spot removal, exile an opposing blocker to push through damage and resetting planeswalkers. If you do this during the end step, they don't get it back until the next end step.
Kitchen Finks