Generation 1: Power Master Optimus Prime
Generation 2: Megatron (Sold him a few years ago, regretting it now
Beast Wars: 10th Aniversary Optimus Primal.
Beast Machines: N/A
Robots In Disguise: Scourge (the only RID I own, heh)
Armada: N/A
Universe 1.0: N/A
Alternators: Shockwave (Shockblast)
Energon: N/A
Cybertron: N/A
Classics 1.0: Bumblebee
Movie: Leader Optimus Prime
Animated: Leader Bulkhead
Universe 2.0: Sunstreaker
Masterpiece: Optimus Prime
Japanese: God Bomber/God Ginrai
As you can see, I pretty much only collect G1 related/inspired stuff.
Cheers!
-Ian