Probably all the stuff that isn't worth much just because of the hassle of selling...
My 845s, r510tp, Superquad, Revolution Blacks, Wilson Staff 1971 Button Backs and my FG-17s, I won't part with them even if I became a crack head.
PING G410 LST w/ Rogue 130 Silver 60x
PING G410 3w w/ Graphite Design AD IZ-7x
Callaway 18° X Forged UT - Graphite Design AD IZ 95x Hybrid
RAW 4-PW Callaway Apex Pro - KBS Tour-Vx
Raw Vokey SM7 50-12s, 54-10s, & 58-10s - DG S400
Scotty Cameron 35" Studio Select Newport 2
Taylormade 35" Spider X
Which clubs will you never sell and why?
Besides my worthless persimmon woods collection, I swear I will never sell these as much as I can, they have very little value anyway.
Bridgestone J33 CB Irons - fitted for me and played for about 10 years, just resting right now
Tommy Armour 845 Irons Silver Scot - 1st real set of irons circa 1990
2 Slighter Seattle putters - one prototype for Blade golf and one custom made gift from my wife and son
My old Ping Anser 3 putter - first putter i bought late 80s
Everything else is fair game.
My copper Epon 302's because they are the most beautiful irons I have ever seen and now very rare so I would have a hard time replacing them.
My Mantis mallet putter. It's as ugly as sin but I have holed so many good putts with it that nothing else comes close.