If you want to check an item's previous sales on marketplace, but there is none currently listed, the thing you want to do, is to search for ANY hat with the wished effect, go to its page, there, you click on the link, and you'll see 3 numbers after /items/.

The last one, with the 'u' in front of it is the effect itself. Then when you have the wanted effect's number, you go back to your hat with ANY effect, and change its number to the one you searched for, I'm pretty retarded when it comes to explaining stuff, so: TL;DR

https://marketplace.tf/items/31016;5;u113/Head%20of%20Steam%20Murderer's

Random effected Murderer Motif

https://marketplace.tf/items/783;5;u16/Vivid Plasma HazMat Headcase

Random Vivid Plasma hat, as you can see Vivid's serial number is 16, so you rewrite Murderers Motif to:

https://marketplace.tf/items/31016;5;u16/Head of Steam Murderer's

and done.