Gheranda Samhita is another text which describes Asanas and Mudras in details. Along with Hatha Yoga Pradipika and Shiva Samhita, it is one the 3 classic treatises on Yoga.
The performance of Asanas is done in order to gain Dhrirata or firmness.
So, Asanas, Mudras etc are practiced as part of a larger Yogic procedure.
The 2nd Chapter of this text deals exclusively with Asanas and the 3rd with Mudras. Mudras given are also very similar to Asanas. For example, Viparatikarani, which is usually considered an Asana, is given under Mudras.
According to Gheranda Samhita there are 84 hundreds thousands Asanas as described by Lord Shiva. Of which only 84 are chief. Of which again only 32 are useful for us.
Gheranda said ---- 1. There are 84 hundreds of thousands of Asanas
described by Shiva. The postures are as many as there are numbers of
species of living creatures in this universe.
- Among them 84 are the best; and among these 84, 32 have been found useful for mankind in this world.
Then in the next few verses the names of these 32 Asanas are given:
So, the 32 Asanas like Padmasana, Bhadrasana, Swastikasana etc .. are mentioned and the procedures of forming them are also given in the subsequent portion of the chapter 2.
The PDF of the text can viewed from here.