Small boat
Sounder mounted to a swivel type rod holder bracket, then I can move it to any rod holder on the boat (leads permitting)
New life jacket rules - life jackets stored on the kids now! frees up a lot of room
Batteries between transom and rear bench seat. 2 Swivel seats mounted on rear bench, to allow me to sit either side, or seat 2 with a full load
Swivel seat on removable mount on middle of front bench seat, allows substitution for a cushion for 2 if carrying a full load.
Aqualizers on boat, allows easy standing for casting moving about etc.
Fishing Anchor mounted at rear for easy use whilst fishing (who wants to get up the front in a mad dash to drop the pick, after you see where you want to be on the sounder). NOT same side as sounder - learnt THAT the expensive way.....
Straight tube Rod holders vertically mounted in strategic spots (transom, front panel) to allow for "pole and hook" for holding dillies while removing crabs, storing landing net vertically etc etc
Often out by myself, or with small kids, so still carry oars rather than canoe type paddles. (Try paddling a 10 foot tinnie solo for a mile if you are wondering why). Makes it harder to stow, but essential.
Electric bilge pump, particulary if you are using a cast net out of the boat!
Couple of those flags on a stick kids put on their bikes, with mounts on trailer. Particulary handy when picking up on narrow bastard ramps that are quiet and you are on your own - where you cant see your trailer because they are so steep at the start. (And the car is wider than the trailer!)
And of course the old "tail lights number plate and reg" on the removable bar that hangs on the back of the boat, for easy removal, and avoiding getting the electrics in the drink!.