Tsrart wrote: I know of only three major paintings that have survived -- Gary Gygax has the Player's Handbook cover, supposedly. A collector I know owns the original Monster Manual cover, and another owns the original Deities and Demigods cover.
I know of one more… The 1st edition
DMG painting by David Sutherland is alive and in capable hands

. It's in nice condition as well.
David unfortunately has passed away, and his family sold what art was remaining in his possession around the time of his death.
I was fortunate to correspond with David before his passing and was entrusted to a few unique items he had in his old TSR treasure chest.
But one item that's not the most valuable, but definitely has the most sentimental value to me - would be Dave's own play-copy of the
DMG. Out of love and respect for the man, and not to forget he was first a gamer through and through, we keep it on the shelf with our other play-copies. I know in my heart Dave would want it that way, in fact I joked with him about it before he passed away.
I'm getting a little sentimental right now, so I've typed enough…
Photos of the Book-

It's the center
DMG.

"Its either a wand to cast Bigby's Hand spells or a +3 backscratcher. We're not sure which."