Perhaps you dont want a powerful Pokemon knocked out, or you want to get all the Energy and Held Items back into your hand for redistribution
10 Immersturm Predator This black and red dragon has been as good as forgotten in the recent Standard meta but just because he's down doesn't mean he's out
OFish, Molten Apple Pie, Big Mac Jingle and Location #1 Win: Free Medium Meal a week for a year (x2,000 to be won)
Blocking an attacking creature with trample with a creature that has first strike can make sure that no damage is assigned by the attacking creature if its destroyed during the first damage step
Ampharos Expedition Base Set / ecard1-34 Energy Connect (Pok-Power) As often as you like during your turn (before your attack), you may take a basic Energy card attached to 1 of your Benched Pokmon and attach it to your Active Pokmon
It also never hurts to have cannon fodder like Forsaken Miner or Bloodghast that can come right back from your graveyard to the battlefield