hariḥ oṁ
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namasté

Many here ( at HDF) practice or aspire to practice some form of yoga. To which, one of the most recognized śāstra on the matter is patañjali’s yogadarśana (the yoga sūtra-s of patañjali). Yet there is a upaniṣad that is connected to sāma-ved called yogacūḍāmaṇi upaniṣad. You may see it written yogacūḍāmaṇyupaniṣad. It is not an introductory-like doctrine.
  • yogacūḍāmaṇi = yoga + cūḍāmaṇi
    • yoga योग = the act of yoking , joining , attaching ; yoga also means a way , manner , method
    • cūḍāmaṇi चूडामणि = gem or jewel
Hence this upaniṣad talks of the gem or jewel ( most valuable) method of yoga. It is made up of 120 śloka-s and IMHO worth considering in one's library.
Perhaps a few choice ideas can be offered here.
praṇām