When in doubt, it can also help you out as well, but this is all about teamwork, right
That said, it all depends on your favorite formats and style of play
Survival of the Fittest is that enchantment, and its effect allows you to add any creature from your deck to your hand, at the cost of G and discarding a creature
You must then build a 100 card deck (including the Commander), but with a couple caveats: You may have no more than 1 copy of a given card in your deck (excluding basic lands) All cards in your deck must only contain mana symbols and colors matching your commanders color identity The Commander rules committee already has a rules document that clarifies all the specifics for how to play, so I wont bore you with any further rehashing here
Usually, we only see white planeswalkers become creatures, although its turned up in other colors occasionally