Lots of blue food handlers sticking plasters not the flesh coloured ones for starters a log book, a first book or guide, some basic babdages, a bottle of stirle water for eye washing if you don't have an eye wash station.Detol type antiseptic, scissors, tape, gause, mouth to mouth guard, a couple of pairs of latex gloves. that should cover the basic's but st'john or red cross sell work place kits ready to go.
You should not have headache tablets,burn creams and the like as they consitutes treatment not first aid.