Starry Night

https://backpack.tf/item/5196085559

Sale 1) Sold + 1 Key for a Steaming War Pig (39 Keys)

https://backpack.tf/profiles/76561198028514199#!/compare/1498608000/1498694400

Low Outlier.

Sale 2) Sold for a Mega Strike Square Dance (57.5 Keys)

https://backpack.tf/profiles/76561198386318724#!/compare/1499212800/1499299200

Rounds to 58 Keys

Sale 3) Sold for 39 Keys

https://backpack.tf/profiles/76561198132226518#!/compare/1499472000/1499558400

Took ~1 Day. Low Outlier.

Sale 4) Sold for a Kill-a-Watt Tipped Lid (57 Keys) + 1 Key

https://backpack.tf/profiles/76561198035586959#!/compare/1499644800/1499904000

http://www.tf2outpost.com/trade/29267424 - Capped by the Buyout of 50 Keys

Sale 5) Sold for a Mega Strike Square Dance (57.5 Keys)

https://backpack.tf/profiles/76561198136662317#!/compare/1499990400/1500076800

Rounds to 58 Keys

https://backpack.tf/item/5254388501

Sale 6) Sold for 40 Keys

https://backpack.tf/profiles/76561198207348327#!/compare/1499904000/1499990400

Took ~2 Days. Low Outlier.

https://backpack.tf/item/5194354881

Sale 7) Sold for a Circling Peace Sign Kiss King + ~1 Key of Items

https://backpack.tf/profiles/76561198037360212#!/compare/1499299200/1499558400

There's no good Mini for the Kiss King. Ignoring.

Sale 8) Sold + 2 Keys for a Green Energy Voodoo Juju (59 Keys)

https://backpack.tf/profiles/76561198191774045#!/compare/1499904000/1500249600

59 - 2 = 57 Keys

Using the multiple lower sales to support 50 being in the range, but since both pure sales went quickly, I'm excluding them and the War Pig sale.