Here are the purposes of the aliens used, excluding Heat Blast and Grey Matter.
Diamond Head: Gwen used it to defeat the drone.
Upgrade: Gwen used it to triple the processing speed on her laptop.
Ripjaws: Gwen used it to get breakfast and lunch.
XLR8: Gwen used it to get some clothes she had forgotten.
Four Arms: Gwen used it to bowl against Ben, getting four strikes in a single frame.
Upgrade: (Omnitrix now on Grandpa Max) Grandpa Max used it to merge and upgrade the RV so it could ram through the ship and reach ground.
User Score: 2786
User Score: 278
User Score: 1500
User Score: 773
User Score: 614
User Score: 504
User Score: 279
User Score: 277
User Score: 198
User Score: 189