Scales for measuring epoxy,
poly bags
solvent for cleaning
make up some carbon or glass plate to use as backing pieces
dust mask
gloves
Have a box for tools and a box for sticky stuff, the sticky box needs a lid so when you pack it in your car you do not get everything else filthy.
7mm and 8mm ring spanners, will do most of the nuts on the boat 4mm, 10mm, 13mm should do the rest.
A set of spanners is a good idea up to 13mm and a even cheap set will be more useful than an expensive shifter spanner. Halfords professional are excellent and not too expensive.
Mole grips
Quick clamps and G clamps
steel rule
tape measure
Box with small compartments to put bolts, screws, shackles in.
Chisel
hammer
Wheel brace that fits trailer
Stanley Knife and spare blades
small block of wood or plastic for cutting ropes on
Lighter for melting ends
Fid for splicing