Personally for quick roadside stuff-
An extendable wheel nut wrench like
this
A set of Torx Tx keys foldable ones like
these should do
A set of Allen keys again foldable like
these
A 10mm spanner
Cross head and straight screwdrivers, or a multibit type one
A roll of electrical tape
A handful of assorted cable ties (they're a lot stronger than you think)
Hi viz vest for standing/working by the road
Pair of 'gardening' gloves to handle dirty wheels after a puncture
Some thin protective gloves (I prefer the nitrile ones) to keep your hands clean
Much more than that and you're starting to carry a lot of stuff that you're not likely to need at the roadside.
ECP links for tools are just to show what I mean not necessarily recommendations for those brands.