I was playing as Chronoranger against Advanced Cosmic Omnitron in the Ruins of Atlantis: I had four bounties out, including By Any Means and The Ultimate Target on the big guy himself (and Jim's Hat and Hunter and Hunted), Legacy had Galvanized and Inspiring Presence, and there was a Phosphorescent Chamber, and I thought to myself "This is going to be good."
Ranger's Mark got another bounty out, which gave me a total of +10 to all damage rolls against the big guy, and dealt 11 damage.
For my second play, an Eye On The Prize for another 11 damage, and an extra play.
Displaced Armory. I went to fetch my Compounded Bow, and dealt another 11 damage.
And then used the Compounded Bow itself for 22 damage.
55 damage in a single turn!
The real tragedy was that Omnitron started that turn with 3 hp so most of that was ludicrous, ludicrous excess, but after losing so many times to him I felt I kind of deserved it.
What's your best "This is going to be a lot of damage" moment?
For me, it wasn't a single turn: more on a single round. We were against Plague Rat, with Meteor Storm in effect, so we were able to set up beautifully. When we were reader, we had Legacy skip his turn to destroy it.
Turn 2: Tachyon. Thre Lightspeed Barrages for 16 each (+1 from IP)= 51
The most effective damage dealer I've seen was... Akash'Bhuta. Hitting herself. It was on Insula Primalis, two fields out, Godmother Earth with ten limbs in play. All heroes were down to 1 or 2 hp, when Fanatic played End of Days.
I don't remember how much damage she did to herself, but I remember she was at more than 100 hp, probably 150. She died.
As for direct damage done by heroes, Absolute Zero was probably my highest hitter, and I have fond memories of Tempest using a boosted Hail for 5 toxic damage on every target (on the Chairman's troops, in the Pike Labs, while Haka had shaken the ground...)
Last night we had a (surprisingly annoying) advanced Voss fight with Bunker, Nightmist, and Haka that ended with Haka unleashing a 16-card Savage Mana with a 22-card Haka of Battle (and +1 for punish the weak) for a 55-point killing blow that took Voss down from like 25 or 30 or so. I don't think that's the most our group has seen, but I can't recall anything bigger at the moment.
My friends and I have been hatching a scheme to play Fanatic and Unity against AKash and see if we can kill here in a single round with end of days play. First have her get out lots of limbs, second have unity get lots of bots and a couple of the ongoing that lets her do damage when a bot is killed (I don't think they are limited). I'm not sure if there is a good way to give Akash bonus damage from a hero, but that would be great.
You could use Argent Adept to Syncopated Onslaught Akash'Bhuta increasing the damage she deals by 1, thus when limbs are destroyed she will do more damage. Also slapping on a By Any Means on here from Chrono-Ranger will also increase the damage she deals to herself. Also a Twist the Ether could increase the damage aswell. So she could deal herself an extra 3 points of damage whenever a limb is destroyed at that point!
I've done the End-of-Days-versus-Ahask'Bhuta thing. I've already mentioned it somewhere before...but she had the "By Any Means" bounty on her and after the limb destruction the damage total was 103. Not enough to kill her but it cleared the field nicely after she'd started to get an uncomfortable amount of cards into play. She was on about 41hp or so after that.
Also managed to get a satisfying win with Haka once - he'd been nomming on citizens and sticking them under Savage Mana. This buffed by my entire hand (around 17 cards or something) in a Haka of Battle dealt a total of something like 34 damage. Dawn only had about 3hp left but I wanted to...erm...make sure she was properly dead, or something ;).
My single turn damage record was agianst Akash'Bhuta (as seems to be quite regular). 129 damage, although it was dealt by Omnitron in the Villain Death Match, so I'm not sure it counts. Electropulse Explosives x 2 plus Sedative Flechettes... Ouch.