In order of converted mana cost:
Dryad Arbor: Forest doubling as a creature, can be put on the field with with fetch lands. Emergency blocker, sac fodder for edict effects, can be fetched with a Chord of Calling for 0 to get a 4th land, played from the top with Courser, fetched to the top with harbinger and so on.
Dragon's Eye Savants: A rarely played card, but he's actually the only modern legal 6+ toughness 2 drop option for this deck! All of the others (only 5 total) either have defender or needs decks built around them. It's great for this deck to have a way to survive a block/trade with Gurmag Angler, a 4/5 Tarmogoyf, Tasigur, the Golden Fang and other 5 toughness threats. The flip ability can come in handy if you have surplus mana, note that flipping morphs is a special action that can't be responded, so there is no window to bolt him, but usually this guy's job is just to be a "6/6" for 2.
Nyx-Fleece Ram: "5/5" for 2 mana that gains you life and can be tutored up with Zur, a given staple of Doran decks.
Spellskite: Already a fantastic card in many decks for protecting yourself and your permanents from all sorts of things, or to steal your opponents auras and buff spells etc. Here where it's also a "4/4" beatstick for 2 mana it's just amazing.
Selfless Spirit: Sligtly nonbo with Doran unfortunately, but the option to secure yourself against sweepers like Supreme Verdict and also protect more imprtant creatures against spot removal is very useful. Also works really well with Chord of Calling.
Courser of Kruphix: Great value and consistency engine, can be tutored with Zur, gets buffed by Doran but also able to deal some damage without him. All in all a great fit and I'd run 4 if it wasn't for the lack of 3 drop slots in the curve.
Sapling of Colfenor: Topping our curve as the only 5 drop, this badboy provides a hard to remove creature that can both hit hard and stabilize our life as well as restock the hand with creatures. Plus he can be tutored up with Treefolk Harbinger. Very useful in grindy games.
