[bad karma]

There is practically nothing in 1:18 scale. Hasbro's Battle Ops Bumblebee was very close, but he doesn't combine with anything to make a bigger robot. There is also Knock Off Transformers that were oversized and fit close to 1:18 scale. We know of ROTF Optimus Prime and Ironhide, but again they don't combine with anything to form a bigger robot and they are expensive. There is also a DOTM Megatron, it's oversized, but still way too small to be 1:18.

That big Voltron Mattel put out last year had pilots that were in 1:18 scale, they did fit inside the Lions, but those Lions were nowhere near the size they should have been to be in 1:18 scale.