The pallet buster is the go-to tool for taking pallet boards off your pallet.
Make sure you get one with an articulating head! Works much better than fixed heads.
Just stick the articulating head under a board and use the handle to pry the board loose from the pallet. It’s very easy and leaves plenty of boards intact.
See my post on Pallet Busting for an instructional video on how well this tool works.