William,
Benefits vary from Tribe to Tribe, as does the 'blood' quantum requirement of each Tribe. Below are the addresses of what is known as the Five Civilized Tribes of Oklahoma:

THE MUSCOGEE (CREEK) NATION

ocevnet.org/creek/Citizen

THE CHEROKEE NATION

cherokee.org/Services/TribalRegistration

THE CHOCTAW NATION

choctawnation.com/

THE CHICKASAW NATION

chickasaw.net/

THE SEMINOLE NATION

seminolenation.com/

Blessings in your endeavor!