Here:
2021.04.23 Chehalis Letter to USSC Clerk of the Court
2021-4-22 ANCs response letter
Confederated Tribes Letter Re Oral Argument Correction 4 20 21 [Ute Tribe/Patterson firm]
Background materials here.
Here are the materials in Mohawk Gaming Enterprises LLC v. Affiliated FM Insurance Co. (N.D. N.Y.):
The complaint is here.
Here (the remainder of the briefs are on the Yellen v. Chehalis backgrounds materials page):
Brief of the Confederated Chehalis Tribes
Here.
Here are the materials in Strange v. Kiowa Tribe (W.D. Okla.):
Here.
Here.