True, and a lot of them are interchangeable.
Transformers team, please notice this.
The recent experimenting with extra heads packed in is encouraging, and I wish they'd do it more (I would have loved for the Retro G1 Bumblebee to have come with both the Bumblebee head and the Goldbug head for your choice of cartoon or toy accuracy). I am 100% behind the idea of standardized head connections wherever possible.