We consider a tree-saver strap mandatory. You can use it for almost anything but this super-strong strap goes around trees, bars, anything you might need to grab. Personally, I carry a tree saver and a longer strap to cover the bases.
Pulley blocks can transform your winch into a pulling beast. By running cable out and around a pulley and back to your machine, you can increase your pull by 2x. That can help you get out of some tricky spots.
Bow shackles are what you use to connect your winch hook to a strap or pulley. These steel parts are built strong and make rigging quick and easy.
A winch line dampner is a good idea to help take out the sting of a failed rope/cable. With proper weighting (I use extra shackles or rocks) the dampner helps get the cable to the ground.
Remotes can be helpful and even safer allowing you to be in a better spot to winch from. From quality wireless to ROAM, our smartphone-capable winching app there are some amazing options in controlling your winch.