I took the trouble to reinvestigate and search, to correct my mistakes and add content.
The Unity Asset Store is the Unity store where you can find several of these models.

"bond1" is a Youtube channel, link here:
   / bond1tgc  

Much of the information was taken from:
https://custard.fandom.com/wiki/Enemies

Thanks to:
Nico_2008
Ignacio Garcia
The Loud Videos 2009
LLAMANDROID

For the contributions.

Music:
   • Slendytubbies 3 The Superiority REMIX...  
   • Slendytubbies 2D: Soundtrack (Menu Mu...