The Saptaratnams are a set of seven pieces composed by Oothukaadu Venkata Kavi. They are:
 

1) Bhajanaamrta- Naattai
2) Aganita mahima- Gaula
3) Madhava hrdi – kalyani
4) Bala sarasa murali- Keeravani
5) Jatadhara Shankara – thodi
6) Alavadennalo – Paras
7) Sundara Nandakumara – Madhyamavati

 
As the name implies, the saptaratnams are similar in structure to Thyagaraja’s pancharatnams i.e. a pallavi and an anupallavi followed by multiple charanams, which are to be rendered as swara-sahitya. However, it is to be noted that the saptaratnams pre-date the pancharatnams by half a century at the very least.
 

All the 7 compositions are in aadi tala and are composed in Sanskrit, except for the 6th which is in tamizh. (Writeup contributed by Akshay Vaidyanthan)