For both a single design as well as a single Variant, I've got a Plethora of Thunderbolts. I've got 19+ Unseen (with at least 1 MIB), then 2-4 more of every official sculpt, plus 4 each of 3 Fan sculpts styled after the Unseen (1 of those in N Scale), then another 4 of the MWO sculpts. All total, I think I've got 56 or so? :D If IWM is ever "Allowed" to produce/release the newly redesigned T-Bolt, I'll buy 4 of them as well! O0
I've also acquired about a dozen each of the Unseen Rifleman and Warhammer, plus about 4 each of the Unseen IIC sculpts for both. I'm not sure about my Reseen counts, except to say that I've got at least 1 of each, plus 4 of the Primitive Rifleman.
Edited to add: I somehow forgot that I've also got 12+ each of the Unseen Goliath and Scorpion minis, with 4 of each Reseen design. That would be an additional 4 Scorpions and 12 (3 Models) of the Goliath. I've got 4-8 of every other Quad ever made, plus 2 Modded Xanthos, giving me over 125 Quads total. :o