I feel like this deck concept is probably best suited towards leaning on a goblin (and Shapeshifter) sub-theme, a Human sub-theme, or an Elf sub-theme, since each is fairly well suited to create loads of creature tokens.  Probably three decks there.  I expect Elves and Goblins are likely more of an aggro theme, with Humans providing more control options.  It would also be very easy to run this with a lifegain side-theme based on creature ETB triggers and lifelink... too many options there.

Cream of the Crop is such a fun card in this deck concept!  It won't take too long before all your crits ETB with +3/+0 (or more), allowing you to pick one of the top 4+ cards for each creature that ETB... granted, in the end you're still just keeping one on the top of your library, but the sheer number of cards you'll see each time you drop multiple creatures in one cast is pure craziness!  Cast a creature that ETB with two more, and assuming each has power 1 and are only getting +3/+0, and you'll be selecting one out of the top 10 cards!  That is soooo easy to accomplish in this deck!  Luckily it's a "may"/optional choice, otherwise you could get into trouble dropping too many large crits at once!  Fun card here!

(add: Electryte; Balefire Dragon; Etali, Primal Storm; Garruk's Harbinger; Imperial Recruiter; Rith, the Awakener; Yisan, the Wanderer Bard; Birthing Pod; Celestial Mantle; Congregation at Dawn; Defense of the Heart; Hoard Hauler; Hunter's Insight; Hunter's Prowess; Mark of Sakiko; Storm the Citadel; Garruk, Unleashed;Nissa, Voice of Zendikar; Vivien, Monsters' Advocate; Elemental Bond; Garruk's Packleader, Garruk's Uprising; Guardian Project; Cryptolith Rite; Minion Reflector; Primal Forcemage; Rabble Rousing; Ruxa, Patient Professor; Sizzling Soloist; Spirit Bonds; Artifact Mutation; Aura Mutation; Curious Herd; Divine Visitation; Eiganjo Uprising; Chitterspitter; Ooze Garden; Thelonite Druid; Sarkhan Vol; Scatter the Seeds (free to cast before your turn begins?); Chord of Calling; Impervious Greatwurm; Nissa's Expedition; Beastmaster Ascension; Heavenly Blademaster; Valor in Akros; Coveted Jewel; Ward of Bones; Fireflux Squad; Aetherwind Basker;

Coveted Jewel is a fun one because it's likely to be very easy to get back if taken away, and therefore justifies your need to attack someone all-out "to get it back".  If it becomes a volley ball amongst everyone, you have a continual reason to attack the controller and not be seen as being a dick, per se.  That being said, if you have an army on the board, no one is likely to piss you off, so you just get to keep hold of it, and even flicker it on occasion if you get Teleportation Circle out, drawing cards and bringing it back untapped.  With the trample/double strike abilities your army will have, along with your sheer numbers, it should usually be easy to retain or regain Coveted Jewel once it's in play.