A new "Mysterious" Badge with 10 undisclosed cards has appeared in Steam's "Badges" section. This is most probably a sign that this year's Summer Sale is imminent. During the last seasonal sales, one extra seasonal card was given to every customer for every badge that he crafted during the sale, and and these seasonal badges formed a set of 10.
This means that right now would be a good time to complete our sets, so that we can craft the badges once the bonuses roll in. :)
I currently have about 1,200 cards in my inventory. If you spot anything that you want, send me an offer. :) I will usually accept every offer that helps me towards completing sets, as long as he cards/sets are of roughly equal value. I don't really mind which sets get completed and which get traded away.
Psyringe's inventory/trade link