Camino de Santiago

All of the following weigh almost nothing, are cheap and commonly available, and could be really useful on the Camino.

Laytex gloves: like the ones used in hospitals. If you're walking in summer maybe you don't want to bring a pair of full size gloves but you'd like to have a fallback strategy in case there's some cold and wet weather (as often happens). If you're walking in winter you'll already be bringing a pair of gloves but it could be handy to have a second pair for extra cold days or for when your main gloves are already wet and are no longer keeping your hands cold. Laytex gloves can also be handy for amateur blister surgery.

Safety pins: cloths pegs (US pins), replacement buttons, zips, self defence, blister surgery (why does it always come to this?)

Masking or Duct Tape: maybe not a whole roll but part of one at least. This can be very useful for quick repairs to clothes or equipment. A small tear in a poncho can quickly turn into a gaping hole. A waterproof jacked snagged on barbed wire may cause a small hole which will let in a surprising amount of water next time it rains. Duck Tape is perfect for these situations (as well as many more).

String: clothes line, shoe laces

Bin bags (US Trash Bags):

Cutlery:

Multi-Socket:

Needle and thread:

Plastic ties

Bubble wrap to sit on