To add to @SpartanMaker’s list,
spare knickers or disposable underwear - diarrhoea is a real possibility & attacks can be extremely sudden.
your own pjs, soap/shower gel. I found putting on my own pjs & using my own shower gel much nicer & sort of soothing than wearing the hospital gown & using their awful anti bacterial soap stuff
all your prescribed medication in unopened boxes/bottles.
Actually I know three others who also have had surgery (different weight & ages) & none of us needed a cane, stomach binder or couldn’t sleep in our bed from day one so I don’t know about ‘most’ needing those sorts of support equipment. Think it’s very individual. Save your money unless you actually need them.
All the best.