I don't actually recommend Doubling Season because it's overcosted if you only use half the card More Counters on Themselves: Avenger of Zendikar especially if you add more fetchlands and land ramp, also Taurean Mauler is a worse Managorger Hydra but still amazing with our commander Draw: The Great Henge, Tribute to the World Tree, Esper Sentinel Ramp: Kodama of the West Tree, Defiler of Vigor, Biophagus Protection: Shalai, Voice of Plenty, Deflecting Swat, Bolt Bend, Heroic Intervention, Teferi's Protection, Clever Concealment, Silkguard Combos: Heliod, Sun-Crowned and War Elemental do the same thing as The Red Terror
All three can produce a good number of rats, and the abilities harmonise with each other
For zero mana, you can tap and sacrifice the Petal to add one mana of any color to your pool
Honestly I like this card for more "fun" games because it gives you opponents something to feed to those annihilator triggers early, so they aren't forced to sit in the game with no permanents and suffer