Monstro's Lung - Every tear in the burst of tears can spawn coins.
Soy Milk - Due to the Soy Milk's high fire rate and low damage, enemies can be hit many more times than usual, resulting in a larger amount of coins dropping.
Technology Zero - Coin tears are connected via electricity. Beams of electricity can cause enemies to drop coins.
Technology 2 - Due to Technology 2's constant fire rate and reduced damage, enemies are hit many more times than usual, resulting in a higher likelihood of coins dropping.