I've seen some promo cards in the current art design (Iron throne edition promos I think) but was wondering if any have been released since then - specifically any promos which have not been reprinted in subsequemt regular sets.

And can they be used in LCG tournaments?

Some of the older promos seem a little powerful too (The Eyrie for one!) but does anyone use them in friendly play and do they unbalance the game at all?

Any links to lists/card art would also be appreciated!

CCG cards are only legal for LCG tournament play if they are IDENTICAL in every way to an LCG card. I don't think that is true of any of the promos...

Check out images of the promos @ AGOTcards.org

I believe the only promos released during the LCG days are alternate art House cards, so nothing that can unbalance the game (alternate art for other cards might be nice, too).