Rockets clear the entire row/column depending on its direction when exploded. Get one by matching any 4 tiles in a row or column.

Bombs remove everything surrounded in a 5x5 square. Matches any 5 tiles in an L-shape or T-shape to get a bomb.

 

Propellers help to clear the 4 tiles surrounding it in a [+] shape, and they also clear one random target when triggered. You can get it by matching 4 tiles in a square shape.

Colorful balls remove all the tiles of the same color from the board. You can match it with other power-ups to multiply them as well.