Stem/bar holder is a bungy cord hanging down from ceiling.
GT85 lids for keeping bolts together, scooping sealant out of tyres, transferring brake oil to a syringe and a million other uses.
Good lighting, whatever you think you need double it and have a small work light nearby to point at fiddly jobs.
Create an upstand around the edge of the floor, you will drop screws and washers and they will roll across the floor and under something too heavy or awkward to move. A little upstand stops this and makes it easier to keep clean too.