I carry...
A cross head screwdriver and spare bulbs so I can change indicator/brake lights.
Fuses
A torch
A tyre pressure gauge
An electric pump
An OBD II reader, to turn off the engine management light
A mobile phone
RAC Membership.
And that is all.
I recently filled the tyres with a liquid stuff that seems to work, in that it repairs minor punctures.
I used in on my bikes, which like a Plus 8, had no spare.