CORE STRATEGY Overwhelm the opponent with an army of token creatures.
First accelerate available mana with Llanowar Elves, Vine Trellis, and Overgrown Battlement. Hopefully 5 or more mana will be available after turn 3. With 5 mana you can cast the main threats, Mycoloth and Bramble Elemental. Mycoloth devours X number of your creatures upon entering the battlefield and receives 2X +1/+1 counters. At the beginning of your turns it produces that many 1/1 token creatures. It is often good to feed it token creatures created in previous turns through Fists of Ironwood.
Mycoloth will often be immediately targeted for removal because it can end the game quickly but this is okay. Your opponent expends a kill spell on it, which allows you to play your more subtle threat, Bramble Elemental. Bramble Elemental produces 2 1/1 token creatures every time it is enchanted. Whip Silk is perfect because it can repeatedly be cast and removed for 2 mana, thus giving you 1 token creature for 1 mana. With 5 mana, Whip Silk can be cast 3 times a turn, netting 6 token creatures a turn. This synergizes with Argothian Enchantress, which lets you draw a card for each enchantment cast. Since Whip Silk can be cast 3 times for 5 mana, you can draw an additional 3 cards a turn and continuously accelerate your mana and army size.
Supplement with Doubling Season for increased volume.
Utility cards include Green Sun's Zenith (for searching for missing/replacement pieces), Lignify (for neutralizing enemy creatures), Utopia Vow (for neutralizing enemy creatures or accelerating your mana), and Fresh Meat (for replenishing your army after a costly attack).
SECONDARY STRATEGY Feed a ton of saprolings to Mycoloth and give it trample via Fists of Ironwood.
TERTIARY STRATEGY Add in Overrun from the sideboard to give all your creatures a stat boost and trample.
SIDEBOARD Muraganda Petroglyphs- A counter against spells and abilities that deal 1 damage globally by giving all token creatures a passive stat boost. NOTE- Cannot be used with Life and Limb. Privileged Position- A counter against powerful targeted removal spells and abilities. Gives all other permanents you control hexproof. Overrun- A tertiary deck strategy. Gives a stat boost and trample to all creatures you control. Prey Upon- A way to remove dangerous non-attacking enemy creatures. Naturalize- A way to remove enemy artifacts and enchantments.
//NAME: Costco Saprolings
4 Vine Trellis 4 Overgrown Battlement 2 Llanowar Elves
3 Mycoloth 2 Bramble Elemental
3 Argothian Enchantress 3 Green Sun's Zenith
4 Lignify 2 Utopia Vow 3 Fresh Meat
2 Life and Limb 4 Doubling Season
3 Whip Silk 3 Fists of Ironwood
//Sideboard 3 Muraganda Petroglyphs 3 Privileged Position 3 Overrun 3 Prey Upon 3 Naturalize