Portuguese Key Chains
Portuguese key chains are the easiest to identify. They resemble small rubber versions of original ponies. On their tummies is printed: ©1984; HASBRO INC. On their inside of one leg is printed: MADE IN PORTUGAL. On another inside leg is printed (looks like): M+B. These have painted bodies (so it tends to rub off over time) along with painted manes, tails, eyes, nostrils, mouth lines and symbols. They also have molded painted tail ribbons. There symbol is on both sides of their bodies. These are also made of hard rubber (PVC). They are about 2" tall and 2" long.
There appears to be four types: Earth pony, Unicorn, Pegasus and Baby Sea Pony. I'm sure there are more than what I have listed below, but this is what I have found so far. Earth ponies are in a standing pose (on their tip toes), unicorns in a walking pose, pegasi in a standing pose with one leg bent, and baby sea ponies are in their floats. As the name implies, these are key chains, and they should have a loop on their neck/back (for earth, unicorn & pegasus) or head (for sea ponies). So far I have discovered 2 earth ponies, 2 unicorns, 2 pegasi and 3 baby sea ponies.
Tummy marks:

Earth
Applejack

Peachy

Unicorn
Pinwheel

Starflower

Pegasus
Firefly

Heart Throb

Baby Sea Pony
Surf Rider
*Ahrian needs this!
Picture Property of Dream Beauty - Used with
Permission
Sea Shimmer
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Tiny Bubbles
*Ahrian needs this!
These are extremely hard to find.
Sell for ~ $4-$10 each.