A magnet tipped extendable probe, and a pair of bookends for times that things need stacked and held, up on the top shelf.
UFO led light on my 550. Makes it WAY easier to make sure everything is ok while loading.
What have you bought, that isn't necessary, but really makes life easier for you?
Amen, brother.....Church Key; it's the last tool I use every time I finish a reloading run.
Satellite radio. Can't beat Frank and Sam and Dean when you are building some ammo.