The best brainrots in Steal a Brainrot, based on income per second and rarity, are mostly from the Secret tier. Top brainrots include:

• Garama and Madundung: Cost $10 billion, income $50 million/second, Secret rarity.
• Strawberry Elephant: Cost $500 billion, income $250 million/second, OG rarity.
• Dragon Cannelloni: Cost $100 billion, income $100 million/second, Secret rarity.
• Ketchuru and Masturu: Cost $7.5 billion, income $42.5 million/second, Secret rarity.
• La Supreme Combinasion: Cost $7 billion, income $40 million/second, Secret rarity.

These brainrots provide the best money-making potential in the game and are highly sought after due to their high income rates and rarity. The highest income brainrot is Strawberry Elephant, while some of the top secret brainrots like Garama and Madundung also provide impressive returns. To get these units, players often need to either buy or steal them, and secret brainrots have very low spawn rates making them rare to obtain.