W Cassettebots (link)

Despite their introduction in the cartoon movie (or probably because of the trauma from seeing it), the G1Autobot cassettes were not that well known (though they all appeared in Season 3 of G1). Decepticon Ratbat was probably better known than Ramhorn, Eject, Rewind, and Steeljaw, followed by Overkill and Slugfest, and then a few more tape characters that barely had robot modes (and combined to form what passed for "robots").

The Headmasters series in Japan however featured other characters, including four cassette figures referred to as the dinocassettes in this article with some great pictures. Check it out.

I don't have these figures. I've SEEN them, whooptie do. They are bizarre looking and barely pass as robots or robot animals. They are also supposedly very rare and insanely expensive on the collector side. Anyway, check out that link, it's a good breakdown and some great pictures.