I have one (maybe two) Native American lines in my family tree. Genetic testing has confirmed this presence, but tracking down some specifics with deceased grandparents whose own parent or grandparent was of a certain tribe make things a little difficult to track when they're deceased and the stigma of being a Native American was considered a "bad thing" at that time societally.
The article How Do I Legally Prove Native American Ancestry? by Henry Louis Gates Jr. and NEHGS Researcher Meaghan E.H. Siekman really points one in the right direction for documentation purposes. This points to the even more helpful document from The Office of Public Affairs-Indian Affairs: A Guide to Tracing American Indian & Alaska Native Ancestry
The common factor seems to be that one must track their lineal descent (see page 5 from above PDF):
... it can be said that two commonly found requirements for membership are: 1) lineal descent from someone named on the tribe's base roll [a "base roll" is a tribe’s original list of members as designated in a tribal constitution or other document specifying enrollment criteria] or 2) lineal descent from a tribal member who descends from someone whose name appears on the base roll. Other conditions such as tribal blood quantum, residency, or continued contact with the tribe also are common.
This got me thinking about certain tools online that make finding certain relatives easier by accessing online services to establish matches. Such services are Veteran Finder, Relative Finder and Pedigree Pie.
Are there any online databases or similar options that facilitate efficient research for American Indian (Native American) ancestry?