My current setup on my gravel bike is a small specialized saddle bag and a "lead-out gear" handlebar bag.
Saddle Bag:
Tubolito Tubes (x2)
Park Tool TB-2 (tire boot)
Muc-Off Co2 inflator kit
tire levers, misc Allen keys
Handlebar Bag:
iPhone, car keys, wallet, wolf tooth Pack Pliers with 2...