How to quickly get rid of various game keys ?

No offense, but I just checked your trade thread and you are asking too much for bundle games.

You're asking still for triple or double the price of the games being sold

Try selling 2 games for 1 key, or 3 games for 2key, or something like that. First, people love to get more ( 2>1, 3>2), secondly, you're selling your stuff horribly expensive, and when people know that it will be cheaper on the sale in one week, no way that they'll buy it. ( Awesomenauts, Talisman)
Try re-constructing your deal - group the origin keys, and as you stated, (Can trade both those Origin keys for 1 key total- it's quite good price for MoH and Mirror's Edge, though origin, so who knows) try selling them 2-for-1-key. Group the games you said "TBH I may toss it for free to any game as bonus". Don't be the cheap buy that asks for money while stating you can also give it for free - simply group them and say that the buyer can pick one for every 1 key paid, or something like that.
Key for succesful selling that you need to get the people they want to buy it. Make it fair in price, throw in the "free" word for the bonuses instead of the "ehhh, I can do that..." mentality - can't guarantee anything so close to sales, but tbh your trading post looks like you only want to get rid of your keys, without properly pricing them or format the text