I'm curious... What don't you leave home without? I'll start..
I always keep: small ratchet/screwdriver set: 5/16-3/4" (which is too small, looking for a better one), small hammer (you never know), a roll of duct tape, spare Napa Gold fuel filter and WIF sensor, strap wrench, PPE WIF wrench, Diesel 911 (in the winter), 4-way tire iron (because the one they give you sucks), first aid kit, 3"x30' recovery strap (10k work load) and clevis, jumper cables, 4D maglite, and maybe a few other odds and ins I'm forgetting.
I always keep: small ratchet/screwdriver set: 5/16-3/4" (which is too small, looking for a better one), small hammer (you never know), a roll of duct tape, spare Napa Gold fuel filter and WIF sensor, strap wrench, PPE WIF wrench, Diesel 911 (in the winter), 4-way tire iron (because the one they give you sucks), first aid kit, 3"x30' recovery strap (10k work load) and clevis, jumper cables, 4D maglite, and maybe a few other odds and ins I'm forgetting.