Most Damaging Non Ultimates

475. but it still loses to most things here.

Also, this question is to ambiguous, it needs to be a little more exact, or Rot/ Heartstopper Aura/scaling spells auto-win(or come extremely close) due to infinite and/or unpredictable damage.

If you out-rule those, it goes to sandstorm when fully channeled. (8000 damage)

After that it depending on whether you count damage from all targets hit by AoEs, but overall it goes to:
1: Chaos Meteor(2444, although that's not exactly right, I wasn't sure whether there were nine or ten ticks of the meteor, so i used a fraction of a tick(it is first place after sandstorm regardless))
2: Ion Shell(1800)
3: Diabolic Edict(1600, although physical)
4: Shrapnel (3 casts is 1584)
5:suicide squad, attack!(1550, although physical)
6: Firefly(1440 with no stacks of Sticky Napalm)
7: Flame Guard(1200, ahead of Battery Assault because not damage is not split up)
8: Battery Assault(1200)
9: Fire Spirits(1120)
10: Shrapnel (2 casts is 1056)
11: March of the Machines(average is 704)
12: Blade Fury(700)
13: Rocket Barrage(690)

If you count only instant damage it goes to suicide squad, attack!, with no real contenders

Notes:
1: I am awful at formatting. Sorry.
2: Remember that sandstorm is not actually in the list, so add one to each place if including it
2: I excluded Poof due to it being 5 casts, not one cast. if included it goes in at 7th place, just before Flame Guard.
3: I excluded anything that scales, creates an illusion or minion, or modifies an attack, including, but not limited to: Sleight of Fist, Overwhelming Odds, Midnight Pulse, Metamorphosis, adaptive strike, anything that spawns illusions, etc...
4: If you counted the actual maximum March of the Machines damage, it would be 5760, placing it ahead of chaos meteor (but still behind sandstorm). Not really going to happen, so I used the average value.
Edit: so many errors. Please pretend i can use grammar.

Sigh. everyone goes with suicide squad over land mines for techies.

Good stuff, though, I'd love to know what Firefly does with, say, 5 stacks of Sticky Napalm (5 stacks is very doable).

Needs to be more of a split between spells that deal the damage instantly, and those that deal damage over time.

It's all well and good saying that technically the Chaos Meteor can 1 shot someone, but it's really easy to avoid unless you're locked in place.

Sun Strike, as another example from Invoker, deals the damage instantly.

Same explanation as poof, using this system, it would be a mine, not a mine stack, and would reach only 600 - behind rocket barrage.

Correct, I think. For theatrics, 10 stacks of Sticky Napalm is 5940 damage

I included that with my last sentence. suicide squad, attack! wins with no contest. That aside, this is not exactly a practical topic, considering that it began with Shrapnel, which rarely does more than two hundred damage. It is more theoretical, seeing how much damage they could deal in a perfect scenario.