Like the OP I am a bit of a Runebound freak as well. I am close to completing the set. While I regard the missing pieces as support/peripheral and not core to the game, I still want the following:
Runebound: Midnight I have found that the ones for sale are a little to steep to bother with, so have been hoping to trade for it...
2 Character Decks Battlemage & Blade Dancer I just started grabbing these as I didn't have much interest in them, but now that I have 4, need them all!
3 of the Promo figures Jonas the Kind, Truthseer Kel, Tobin Farslayer I hardly count these, but considering I have both Runewars and Descent I might as well try to get them. I ended up with Nara The Fang when it was included in my order of Descent: The Road to Legend unexpectedly. Prices for these figures are a little absurd though so Im in no real rush. But if I can get them in a trade I would be happy.
While not as close as you, I am close so I understand the need to get those last pieces. Thankfully I managed to get Terrors of the Tomb...its a nice card pack too!