Central Intelligence

https://backpack.tf/item/2489241432

Sale 1) Sold for a Power Surge Your Worst Nightmare (35 Keys)

https://backpack.tf/profiles/76561198088171813#!/compare/1546646400/1546732800 - Seller's Backpack

https://backpack.tf/profiles/76561198119149660#!/compare/1546560000/1546646400 - Buyer's Backpack

https://backpack.tf/item/2344450054

Sale 2) ?

https://backpack.tf/profiles/76561198223191956#!/compare/1547078400/1547164800 - Seller's Backpack

https://backpack.tf/profiles/76561198119149660#!/compare/1547078400/1547164800 - Buyer's Backpack

https://backpack.tf/item/2253115713

Sale 3) Sold + 4 Keys for a Death at Dusk Ol' Snaggletooth

https://backpack.tf/profiles/76561198215559840#!/compare/1539907200/1539993600

https://backpack.tf/profiles/76561198140928358#!/compare/1539734400/1539993600

I can't figure out a Mini for the Snaggletooth.

Sale 4) Sold + 3 Keys for a Green Energy Head Hedge (29 Keys)

https://backpack.tf/profiles/76561198140928358#!/compare/1540512000/1540684800

29 - 3 = 26 Keys

Sale 5) Sold for a Disco Beat Down Backbiter's Billycock (23.5 Keys) + 2 Tour of Duty Tickets + Russian Arms Race (just under 2 Keys together)

https://backpack.tf/profiles/76561198153417214#!/compare/1543017600/1543104000 - Seller's Backpack

https://backpack.tf/profiles/76561198357301658#!/compare/1542844800/1543968000 - Buyer's Backpack

23.5 + just under 2 = just under 25.5, which rounds to 25 Keys

Billycock Mini

https://backpack.tf/suggestion/5c44e264cf6c7561be226b48 - 23.5 Keys

https://backpack.tf/item/1976476739

Sale 6) ?

https://backpack.tf/profiles/76561198306724981#!/compare/1544140800/1544400000

https://backpack.tf/profiles/76561198155412687#!/compare/1543968000/1544140800

Sale 7) ?

https://backpack.tf/profiles/76561198155412687#!/compare/1544140800/1544227200

https://backpack.tf/profiles/76561198367551064#!/compare/1544140800/1544227200

Sale 8) ?

https://backpack.tf/profiles/76561198155412687#!/compare/1544227200/1544313600

Sale 9) ?

https://backpack.tf/profiles/76561198335791307#!/compare/1545696000/1545782400

https://backpack.tf/profiles/76561198797664044#!/compare/1545782400/1546041600

https://imgur.com/a/aULhQW1 - The sale was supposedly 30 Keys

Sale 10) ?

https://backpack.tf/profiles/76561198797664044#!/compare/1546041600/1546300800

Sale 11) Sold for a Sunbeams Puffy Polar Cap (33 Keys)

https://backpack.tf/profiles/76561198119634686#!/compare/1546473600/1546560000

https://backpack.tf/profiles/76561198147248917#!/compare/1546300800/1546560000

Sale 12) Bulk sale

https://backpack.tf/profiles/76561198147248917#!/compare/1546300800/1546560000

Sale 13) Sold for 22 Keys + 20 Refined

https://backpack.tf/profiles/76561198288023134#!/compare/1547078400/1547164800

https://marketplace.tf/items/388;5;u62;strange - Sold for $35.14 (low) and $59.99 when Keys were ~$1.76 each

https://marketplace.tf/items/5021;6/Mann%20Co.%20Supply%20Crate%20Key

59.99 / 1.76 = 34.08, which rounds to 34 Keys

https://imgur.com/a/4MWEbzg - 1 Day Seller at 32 Keys, 9 Day Seller at 34 Keys

https://backpack.tf/item/2344450054

https://backpack.tf/item/1976476739