All insulated(Screwdriver,pliers,side cutters,longnose pliers, cable strippers).
Testers various.
Spanners,step ladders,ladders,dust sheets,hover,dust pan and brush.
Crimping set and various types of crimps, earth bond straps.
Various pins and nuts and bolts for fixings raw plugs screws.
Sds drill with hammer stop,Batt drill,maybe jigsaw or recipricating saw.sds masonory drill bits,wood drill bits and metal drills bits,chisels,chasing out bits.
Plus you would prob need to get some sockets and light switches to keep for stock and some cable 1.5,2.5 T&E allways best to keep some on van.
Dependent on testers i'd say