Resuggestion, thanks to Cashew for the info!

Sale 1:

https://backpack.tf/profiles/76561198099290215#!/compare/1546819200/1546905600

https://backpack.tf/profiles/76561198151731595#!/compare/1546732800/1546819200

Untrace

Sale 2:

https://backpack.tf/profiles/76561198151731595#!/compare/1546819200/1546905600

https://backpack.tf/profiles/76561198151731595#!/compare/1546819200/1546905600

QS?

Sale 3:

https://backpack.tf/item/277010243

All gambling

Sale 4:

https://backpack.tf/profiles/76561198289040457#!/compare/1550016000/1550102400

https://backpack.tf/profiles/76561198061716132#!/compare/1550016000/1550102400

Bulk

Sale 5:

https://backpack.tf/profiles/76561198061716132#!/compare/1550102400/1550188800

https://backpack.tf/profiles/76561198289040457#!/compare/1550102400/1550188800

Sold with ~20 keys in sweets for Miami Brainiac

bulk

Sale 6:

https://backpack.tf/profiles/76561198289040457#!/compare/1550361600/1550448000

https://backpack.tf/profiles/76561198337734785#!/compare/1550361600/1550448000

QS

Sale 6:

https://backpack.tf/profiles/76561198337734785#!/compare/1553299200/1553385600

https://backpack.tf/profiles/76561198121991829#!/compare/1553299200/1553385600

Sold for 30 keys

Sale 7:

https://backpack.tf/profiles/76561198121991829#!/compare/1553385600/1553472000

https://backpack.tf/profiles/76561198173073890#!/compare/1553385600/1553472000

Sold with 5 keys for PE Guad

Use there

Seller for 33, unsold for 2 months, unsold for 1 month,

Cashew Mini:

https://backpack.tf/item/267972500 seller at 27

https://backpack.tf/profiles/76561198173073890#!/compare/1554508800/1554681600 sale at 26

https://backpack.tf/profiles/76561198172458063#!/compare/1554940800/1555027200

https://backpack.tf/profiles/76561198314776045#!/compare/1554940800/1555027200 maybe another sale at 26?

Taking 26 - 30 keys, seller at 27 is young.