Where are those giveaways coming from?

from a shady extension

Masafor says, " links to that site aren't allowed at sg".
Sorry, I removed it.

Fanatical : The Magnificent Mystery Machine

From a previous Humble Monthly :) I think May's.

Fanatical's Mystery Bundle

Mystery fanatical or Humble Tinybundle (already end)

Fanatical kalypso bundle

It's also one of the possible keys of The Magnificent Mystery Machine (Fanatical)

https://www.steamgifts.com/discussion/AUxx5/fanatical-assemble-bundle

Fanatical Mystery

Indigala bundle: https://www.indiegala.com/radical-mix-indie-steam-bundle

Looks like Fanatical have it on discount in their store

And it's also in The Magnificent Mystery Machine (Fanatical)

Would like to know also

Both from Fanatical Mystery

https://www.steamgifts.com/discussion/tHaRx/fanatical-fugitive-bundle

https://www.steamgifts.com/discussion/tHaRx/fanatical-fugitive-bundle

I think it was an Indiegala giveaway:
https://www.epicbundle.com/article/steam-key-for-free-the-dark-stone-from-mebara
Before they stopped doing steam key giveaways.

It was in many many bundles a couple years ago, including one of the big "$1 bundles" from Bundle Stars/Fanatical, so my guess is they are leftovers from those old bundles.

https://www.steamgifts.com/discussion/PgFsE/bundle-stars-dollar-monster-bundle
1 tier, 50 total
1 dollar, 50 games