Give me your ideas. If you can only hit that ability once, at level 1 to do the most damage as possible, which champ would do the most damage(meaning that you cant spam veigar q for 1 million stacks). You can charge the ability, (Varus's Q). And even auto before hand for a proc, (Vayne's w 3rd shot).
In realistic mode 
Tiger stance double dot Around 250+aa damage with a long sword start.
In super lucky mode
W That hits 5 members 375+ 4% of each persons health
In something that would never happen mode 
places a E on the floor hitting 5 members and then opposing team dashes/knocked back through every brick doing a little over 1k damage.
Sion Q fully charged.
Q
not really a single ability, but the fact that you can spam at level 1 is really good
Q since it proc their passives
Q before the nerfs if all the rock connect
fully charged Q.
Q plus passive
Q plus auto
Q if all 3 connect
Pretty sure everyone is forgetting Fiddlesticks W... It does like 250 dmg with no items, and Domination / Sorcery to the 100 MR target dummies level 1.
Sion Q does like 95 no items Aatrox all 3 Q does 150 Taliyah Q does 142 dmg so Fiddle W wins out at 250
Q full charge
Q played right
And it seems like you're not allowing it but Q with all 3 charges (since it's technicality one ability) definitely would win
The top would be Karthus or Fiddle for channeling. Fiddle dam is insane at level 1 if they stay in range. Even Pantheons can be pretty nasty although his E is cast over time and not really a channel.
For nonchanneling:
Nidalee - spear or Zoe Q wins easy at max distance.
Other champs that all have high 1 skill damage: Ahri/Ekko/Sivir - If their Q hits both times. Kai if there is only 1 target near.
For a few patches Taric's stun had 105 base damage at level 1
So guys! I have done some research and 
actually does the most damage if u stack spears infinitely, then use your e! sorry guys... lmao
Me and Akali
