Primer
Card Choices Avatar of the Resolute - An overloaded but severely underutilized card. Can be as big as a 7/6 Reach Trample Turn Four for two mana. It's only downsides are requiring GG to cast, which can be annoying, and Reach and Trample on the same creature aren't very synergistic. Do you attack or block with it? All the same it's great so run four copies.
Chasm Skulker - Another overloaded creature. A 2/2 with no abilities upfront doesn't sound great. However it gets a +1/+1 counter every time you draw a card. Better. Then, when it dies you get a 1/1 token with Islandwalk for each counter on it. So yeah, great card. I would go with three copies because we have a number of other competing cards.
Cloudfin Raptor - These are best when played early, since they trigger evolve off of almost everything. Additionally they let us chump flyers, and beat if needed once they get a little bigger. It doesn't become useful for a few turns, or have any utility, but for one mana this I'll take three copies.
Experiment One - Another favorite card of mine, ever since I earned a couple promos at an FNM event. Great promo art too. This doesn't have the evasion of Cloudfin, but it has a conditional regenerate, which is critical for a deck with no removal and only a few counterspells.
Scavenging Ooze - This guy seems plenty of play in various green decks, but he fits in here too. Hates on Tarmogoyf, hates on Reanimator, and hates on Delve, all while getting bigger and gaining us life. It's rare that a sideboard type card is mainboard playable, but Scooze is. Three copies.
Vorel of the Hull Clade - In short, he's a Bolt-Proof blocker who lets us pay UG to double the counters of a permanent we control. Alternatively, use it to put more bad counters on an opponents creature. Usually I'll do it to put a second -1/-1 counter on a persisted Kitchen Finx, to kill it right away. It has a few other situational uses. Legendary, so three copies.
Serum Visions - Consistency, card draw for triggering Chasm Skulker, and overall value. Four copies. You can run Peek or Gitaxian Probe if you want to keep tabs on your opponent, but I prefer the scry.
Hardened Scales - This adds an additional source to every counter generation method. It's one mana and will often give you free 4-6 counters per game, if not more. More is good, so four copies.
Collected Company - This basically flips any creature in the entire deck. I see a lot of people running three because they get flooded, but I have more success with four.
Simic Charm - Doesn't directly generate counters, but every mode is useful and it gives us some much needed utility. Two copies because its over costed.
Remand - We have little interaction with our opponents, little life gain, and no card draw, so this helps fill some gaps while stalling combo decks. Three copies.
