The Answers for Wordscapes Level 56599 from the Arch 16 pack and Master group are: deer, desert, deter, red, reddest, reset, rest, rested, see, seer, set, steer, tee, terse, and tree.
Just a heads-up: the puzzle layout on Master levels is autogenerated, so the grid you see here might look a little different than the one in your game.