Playmates are Dam trolls that are about 5 inches. They have been made since the late 1960's, and have had a large variety of faces. For older Playmates, they even had different body types.
When it comes to collecting, it can sometimes be a little confusing to know when a certain Playmate was made. Dates are funny - the date listed on trolls is the date the mold for the troll was made, not necessarily the troll itself. For Dam trolls in general, you can sometimes even have two different dates on a troll (one for the head, and the other for the body), though this is not the case for Playmates.
You can usually tell around when a Playmate (all Dam trolls really, but I find especially with the 5 inch Playmates) was made by what type of stamp is on the bottom of their foot. One example I posted shows 4 generations of the same faced Playmate, and how the stamp changed for each one. On the example I wrote out what each stamp says since it was outrageously hard to get my camera to take a legible photo of them :-/.
1)Made in the 1960's/70's : they tend to have a foot stamp with the date obliterated by another round, deeper stamp that I suppose was supposed to have the date on it. If you can read the deeper, circular stamp, it appears to be backwards.
2)Made in the 1980's/90's.
3)Made after the year 2001, but not for very long.
4)Made after 2005.
Another way to tell when the Playmate was made is how their body is constructed. I made another example showing an older version (bigger hands that often turn out or in, and often one hand will be held out, and stockier legs) vs a more newer version (arms always stick straight out, slightly thinner arms and legs). The older Playmates are also made of softer vinyl, whereas their newer counterparts are harder.
Little Sisters and BrothersThe older Playmates are also called Little Sisters and Brothers. I personally love them - there are some faces they did not continue to make, which is such a shame! They are so full of character! Long Standing Goal: collect every older Playmate face :-). They also came in felt outfits with rivets holding them together in the front. Unlike their descendants (who are very common), the Little Sisters and Brothers are not as easy to find (especially still clothed in their distinctive, riveted original outfits). Also unlike later Playmates, they came in two genders (later Playmates came only in little, non-riveted dresses).
Here are two clips from an ordering magazine showing the variety of faces and body types they came in: