At least three of these accessories will fit in even a small Christmas stocking and the fourth will likely qualify as a stocking stuffer for a standard-sized sock. Having them in your kit will, for many, be worth the mostly stocking-stuffer-sized prices:
Super Clamp
Magic Arm
Double Ball Joint Head
Tripod Head Mounting Plate with Hex Stud
These reviews are primarily to highlight what I'm using and find useful, but ... being able to reference these items will be helpful for an article I hope to have ready for you on Monday.