A pail of water.
Definately.. Otherwise the sticky mess will overwhelm you..
Some good suggestions..
If there is no power I take my generator. Ladder, hive tool.. Invaluable for cutting comb from walls and scraping walls clean. A good knife.. I use a filet knife and my hive tool almost exclusively. I have a shorter table knife and a bowie style combat knife but dont often use either..
A trash can to put garbage bags in.. Otherwise you are struggling with the garbage bag to open it every time you want to put a piece of comb into it.. the garbage can holds the bag open and up.. Makes life VERY much easier..
You will need a cats paw and hammer. A flat bar or two to get the batton and boards off. A long filet knife to cut the comb free before you pull the boards away from the walls. Empty frames and rubber bands for the brood comb. At least two boxes worth just in case.
A queen clip is a bonus.. Having the queen in a clip is always a super feeling... If no clip she can be carefully caught and allowed to be sucked directly into the hive/beevac without bouncing through the hose. If no BeeVac she can be put directly into the hive with the brood combs, just use care with her. Shake some bees from cut comb in with her, they usually stay.
Smoker to herd the bees along and calm them.. As Perry said, a bucket of water to wash.... everything... a rag to dip in the bucket to wipe things down with, because somehow.. EVERYTHING gets sticky....