There are two types of boosters that can help you on the levels, pre-session boosters and in-game boosters.

You can obtain Pre-session boosters by watching a short advertisement before retrying a level or by selecting them on tournament levels. By watching ads you can also get one free booster to start the level with. Pre-session boosters such as Coral, Block Smash and the Rainbow fruit can be selected. 

Block Smash Booster – Causes damage to random blocks on a level

Rainbow Fruit Booster – Will destroy all fruit of the same color it is swapped with.

You can select three boosters to start with on Tournament levels. Boosters that can be selected on Tournament levels are Triple Coral, Double Bitelings, Octo, Rainbow Fruit and Block Smash.

In-game boosters include Smash Crab and Octo Strike and can be purchased with coins. You can select a booster by tapping the booster button in the top right side of a level and de-select it by tapping the button again.

Smash Crab – Destroys any target or pile of targets on one tile

Octo Strike – Crushes the target and adds an Octo to the tile you’ve targeted.