Holy nellie!
I was a major Yugioh Fanatic in my time, and, well...
He's got some really good stuff there. REALLY GOOD.
I'll reiterate what's worth selling on eBay:
Harpie's Feather Duster - May not sell due to promo status
Last Turn - This is a gooder
Riryoku - May not sell due to promo status
Negate Attack - May not sell due to promo status
Mirage of Nightmare - This will sell, I'm sure.
Mirror Wall - Good chance of selling.
Exiled Force - Good chance of selling
Reinforcment of the Army (Both of 'em) - Make this in a deal with the Marauding Captain
Spell Canceller - This WILL sell.
Nobelman of Crossout - Good chance of selling.
Marauding Captain - Put in a deal with the Reinforcments of the Armies
Sasuke Samurai - May sell.
Solemn Judgement (EEEE!!! ME WANTS!!!) - This should sell.
Diffusion Wave Motion - This WILL sell.
Royal Command - Good chance.
Mage Power (I WANT!!! AAAHHH) - This WILL sell.
Forceful Sentry - Good chance.
The 2 guys to the left of the Nobleman of Crossout
Dear god, I want some of those... at least he doesn't have Chaos Emperor Dragon - Envoy of the End, heh... I'd have to kill him then.
For all those, I'd say you could get $100 - $200 U.S, but am not totally sure... check those cards on eBay, maybe try some combos with them. All I can say is, I wish I had them...
NOTE: Cards who's holofoil has a hexagonal pattern (indicating promo via GameBoy game) may not sell due to the fact that they're GameBoy promos. However, I'd still want them. You might want to do this: Put all thr promo rank cards into a deal together... you'd likely get a buyer then, thus they only need to buy the cards, and not the GameBoy game to go with.
Heh... a friend of mine has two of the cards I mentioned above... the "Chaos Emperor Dragon - Envoy of the End"... $50.00 US a peice.