What do you keep under your seat? Everything you need to USE a truck... I'll go first...
door pockets:
4 TCW3 quart oil bottles (2 in each side),
small hand tools (multi-tip screw driver, adjustable wrench, multi-tool)
tire pressure guage
work gloves (canvas, leather, rubber)
double ended snaps handy for tie downs & tent set ups
flashlight
I have a plastic bin that fits under each side. I drilled the seat brackets for a short bungie to keep the stuff from sliding out on a hard stop... bungie hook had to be opened so it could go through the bracket.
Front:
tie down ratchet straps, bungies
tow strap & anchor shackles
magnetic wands for trailer hookup
12V power extension cord (10', 14/2 marine harness with cig lighter plug/socket)
roll of paper towels
Back:
Spare fuel filter Dodge can
spare filter set Air Dog
duct tape
trailer hitches (hidden hitch & 2" ball on a reese drop insert). The WD hitch only gets used with the camper & parts store there as well.
Spare Jesus clips & hitch pin.
small hank of Parra cord,
winter front & hardware (off season)
A twin size wool blanket (surplus) on back seat... protects seat & emergency use.
Old towel on grab handle on seat back... for times when wet hands will not do.
Share your ideas...