Some people are really good at keeping records. I'm not one of them, but I have some when I get into my logs. Can I suggest, to avoid confusion, you keep the lists of Hasbro/Tak MPs separate.

Off the top of my head (and leaving out any I have doubts about) we definitely have had:

Hasbro
Optimus Prime (20th Anniversary) (Target)
Optimus Prime (DVD version)
Starscream (Toyworld)
Grimlock (Toys R Us)
Rodimus (Toys R Us)
Optimus Prime (Mp10) (Toys R Us)
Acid Storm (Toys R Us)
Soundwave w/tapes (Toys R Us)
YOTH Optimus Prime (Myer)
YOTG Soundwave (Myer)


Takara
MP03 - Ultra Magnus (Target)
MP04- Convoy (Target)
MP12: Lambor (Toys R Us)
MP21: Bumble (Toys R Us)
MP21G: Bumble G2 Version
MP24: Star Saber
MP25: Tracks
MP26: Road Rage