Metro games are currently on sale up to 75% off on GamersGate. Of course they are Steam redeemable. Pretty cool games!
Stronghold 3 is pretty new to me (currently 75% off), never played it but always enjoyed the original. If you’re craving for some medieval RTS go ahead and get it I guess, it’s Steam redeemable as well.
And the last one on sale is Reus. Looks like fun and also redeems on Steam just fine. 50% off!