These are the smallest ever of the proper ponies (discounting therefore Petites, which I'm not going to even *begin* to get i into on my page) and they were sold in the USA under the name of Teeny Tiny Ponies. However Hasbro in the UK seems to have been undecided on this point. On the cards they were labelled 'Teeny Weeny Ponies', however Hasbro's list also calls them Teeny Tiny Ponies, so they seem to go under either or both names in the UK. Also, it's important to note that Little Lullabye was called Little Tabby in the USA, and for the bizarrest reason Little Rattles (who has a rattle for a symbol) was called Little Whiskers in the US line. We won't even go into the logic of calling a pony Little Honey Pie :p. If memory serves they came on pastel yellow cards with yellow borders (I would have to check my file to be sure, but I'm pretty certain) and they had I think they had duck combs and ribbons.
On her backcard, Little Lullabye was named as being the youngest Teeny Weeny Pony, so, effectively, the youngest Baby Pony (until the Surprise Twins pony produced her twins in 1994.)
I think they look rather like kittens, with their little noses and big eyes. :)