You are seriously remiss if you don't have one of these 3 arm 4/5/6 Allen key wrenches. I have used mine since 22 years ago when I got a modern bike, these things take massive torque. Good for both threaded and not stems, brakes of all kinds, racks, some new pedals, seat bolts.
I carry more stuff than anybody. LOL. So lots of redundancy.
7, 8, 9, 10, 10, 1/2"/ 9/16", 15 mm or 6" crescent for my CCM, metal tire priers, tube, individual Allen keys too.
Tour bike has every tool I ever need. Easily 5 lbs.
Those looped together Allen key multi tools are useless.
Like this one, but get a better one. >>
https://www.walmart.com/ip/Ventura-T...-6-mm/13012559
The Park tool one has a too bulky center.