Both of them have numerous names....
Names for Sita: Bhaumi,Bhumija,Bhukanya- All meaning 'born of earth'
sita/Seeta -literally means a 'furrow' or 'sillion' in rigveda, Sita is the goddess of agriculture.
Other names are Jaanaki, Janakanandini, Janakatmaja, Raamapriya, Ramaa, Vaidehi, Maithili.
Various names of goddess Lakshmi are also associated to Sita.
As for different names for Shri Rama , the list is countless...some of the names are:
Ramachandhra, Ramabhadra-In Valmiki Ramayan, Janak prefers to call Rama by this name.
Raghav, Raghavendra- Valmiki prefers to call Ram ji by these names.
Other names are: Ramaapati, Sitapati/Siyapati,Avadesh, Dasharathi etc
😛 this post is getting too long, hope this helps.