Each booster does its own specific thing:

 

Shuffle booster mixes the tiles so that new pairs available for matching may appear;

Diamond booster collects all diamonds in the correct order automatically;
Bomb booster removes 5 random pairs of tiles from the game board;

 Lock booster unlocks all locked tiles on the level;

 Time booster adds 15 extra seconds to your time on the timed level you're playing at the moment.