Thanks to Shuffle for the info!

Sale 1) ?

https://backpack.tf/profiles/76561198059098316#!/compare/1580860800/1581292800

https://backpack.tf/profiles/76561198817631515#!/compare/1580169600/1582156800

Sale 2) Bulk sale

https://backpack.tf/profiles/76561198817631515#!/compare/1582675200/1582848000

Sale 3) Sold for 13 Keys

https://backpack.tf/profiles/76561198964982078#!/compare/1584057600/1584230400

https://backpack.tf/profiles/76561198175367966#!/compare/1584144000/1584230400 - The 13 Keys going to Scrapprehensive were involved

https://backpack.tf/profiles/76561198057412106#!/compare/1584144000/1584230400 - They were used to buy the Rifleman from Scrap

The Seller used the 13 Keys toward buying the Rifleman to sell for 32 Keys, as seen in the first link

Sale 4) One of the Marketplace sales

https://backpack.tf/profiles/76561198175367966#!/compare/1585526400/1585612800

https://backpack.tf/profiles/76561198086215459#!/compare/1586131200/1587340800

https://backpack.tf/item/7033446265

Sale 5) ?

https://backpack.tf/profiles/76561198028188341#!/compare/1582934400/1583366400

https://backpack.tf/item/6165831738

Sale 6) Sold for 13 Keys

https://backpack.tf/profiles/76561198305494036#!/compare/1586476800/1586563200

https://backpack.tf/profiles/76561198448089440#!/compare/1586476800/1586649600

The IDs match and the Bat Hat in the buyer's compare sold to Uncle Dang's Dispenser, from whom the Keys come

https://backpack.tf/item/8594031790

Sale 7) ?

https://backpack.tf/profiles/76561198370591649#!/compare/1585008000/1585094400

https://backpack.tf/profiles/76561197993888396#!/compare/1585008000/1585094400

Sale 8) Sold for 14 Keys

https://backpack.tf/profiles/76561197993888396#!/compare/1585440000/1585612800

https://backpack.tf/profiles/76561198345751006#!/compare/1585440000/1585526400

Sale 9) Sold for ~14 Keys of Items

https://backpack.tf/profiles/76561198345751006#!/compare/1585612800/1585958400

https://backpack.tf/profiles/76561198899257220#!/compare/1585872000/1585958400

Sale 10) ?

https://backpack.tf/profiles/76561198899257220#!/compare/1585958400/1586044800

Sale 11) Sold for 13 Keys

https://backpack.tf/profiles/76561198358296372#!/compare/1585958400/1586044800

IDs match

Sale 12) ?

https://backpack.tf/profiles/76561198105359319#!/compare/1586649600/1586736000

Sale 13) ?

https://backpack.tf/profiles/76561198305494036#!/compare/1586649600/1586736000

Sale 14) ?

https://backpack.tf/profiles/76561198304302520#!/compare/1587686400/1587772800

https://backpack.tf/item/5905781572

Sale 15) Sold for 18 Keys

https://backpack.tf/profiles/76561198197828049#!/compare/1580515200/1580860800

IDs match. High outlier.

Sale 16) ?

https://backpack.tf/profiles/76561198195711453#!/compare/1569542400/1585872000

Sale 17) Sold for 15 Keys

https://backpack.tf/profiles/76561198258937500#!/compare/1586044800/1586131200

Sale 18) Bulk sale

https://backpack.tf/profiles/76561198258937500#!/compare/1586217600/1586304000

https://backpack.tf/profiles/76561198275012706#!/compare/1586217600/1586304000

The Capotain and Taunt are included for the Keys

Sale 19) Quicksold for 11 Keys

https://backpack.tf/profiles/76561198275012706#!/compare/1586217600/1586304000

https://backpack.tf/profiles/76561198341480941#!/compare/1586217600/1586304000

Sale 20) ?

https://backpack.tf/profiles/76561198341480941#!/compare/1586304000/1586390400

https://backpack.tf/profiles/76561198279083007#!/compare/1586217600/1586304000

Sale 21) Quicksold for 12 Keys

https://backpack.tf/profiles/76561198279083007#!/compare/1586304000/1586390400

https://imgur.com/a/l7t7BWA - 3 bot.tf buys at 11 Keys support 18 being excluded as a high outlier

https://marketplace.tf/items/tf2/30863;5;u62 - Sold for $28.17 when Keys were $1.69, $27.49 when Keys were $1.72, and $28 when Keys were $1.77

28.17 / 1.69 = 16.67, which rounds to 17 Keys

https://imgur.com/a/YPLeiOO - The 17 Key sale is capped by the buyout of 15 Keys (Vader)

27.49 / 1.72 = 15.98, which rounds to 16 Keys

28 / 1.77 = 15.82, which rounds to 16 Keys

https://imgur.com/a/Klt1RdO - The $28 sale is capped by the buyout of 15 Keys

Total sales @:

11, 12, 13, 13, 13, 14, 14, 15, 15, 15, 16, 18 keys

buyers up to ~1 keys,

calling 12 low, 18 high,

taking 13 - 16 keys.