Among all the United States Supreme Court cases that definitively support damages against the states, this first one appears to be one of the "granddaddies", in terms of explaining why the state is liable, lists the cases further below in support, and is provided here, along with the other samples. (And, again, there are many other cases from both the USSC, as well as the 13 Federal Circuits, too...).

Verizon MD. Inc. v. Public Serv. Comm'n of MD.
000 U.S. 00-1531 (2002) (a.k.a. 535 US 635)

Compare, e.g., Board of Trustees of Univ. of Ala. v. Garrett, 531 U. S. 356, 360 (2001) (money damages from the State as employer under Title I of the Americans with Disabilities Act of 1990); Kimel v. Florida Bd. of Regents, 528 U. S. 62, 66 (2000) (money damages from the State as employer under the Age Discrimination in Employment Act of 1967); Alden v. Maine, supra, at 712 (money damages from the State as employer under the Fair Labor Standards Act of 1938 in state court); Florida Prepaid Postsecondary Ed. Expense Bd. v. College Savings Bank, 527 U. S. 627, 633 (1999) (money damages and injunctive and declaratory relief against a State for patent infringement); College Savings Bank v. Florida Prepaid Postsecondary Ed. Expense Bd., 527 U. S. 666, 671 (1999) (same for trademark violations); Seminole Tribe, supra, at 47 (suit to compel State to negotiate in good faith); Hans v. Louisiana, 134 U. S. 1 (1890) (money damages for failure to honor state securities). In Seminole Tribe, a majority of this Court observed "that the relief sought by a plaintiff suing a State is irrelevant to the question whether the suit is barred by the Eleventh Amendment," 517 U. S., at 58, but this was said in the context of a suit for injunctive relief (to enforce a duty to negotiate) as opposed to money damages. My point is that conventional relief of both sorts (and declaratory relief) is different in kind from the judicial review of agency action sought in these cases.

citing: "Fitzpatrick v. Bitzer, 427 U.S. 445 (1976) (concluding that Title VII's authorization of federal court jurisdiction to award money damages against a state government to individuals subjected to employment discrimination does not violate the Eleventh Amendment since Congress was exercising its §5 remedial powers)"

"On the other hand, although prospective relief awarded against a state officer also "implicate[s] Eleventh Amendment concerns," Mansour, 474 U.S., at 68 , the interests in "end[ing] a continuing violation of federal law," ibid., outweigh the interests in state sovereignty and justify [491 U.S. 58, 90] an award under 1983 of an injunction that operates against the State's officers or even directly against the State itself. See, e. g., Papasan, supra, at 282; Quern v. Jordan, 440 U.S. 332, 337 (1979); Milliken v. Bradley, 433 U.S. 267, 289 (1977)."

"On the Court's supposition, the question would be whether the complaint against a state official states a claim for the type of relief sought, not whether it will have an impact on the state treasury. See, e. g., Governor of Georgia v. Madrazo, 1 Pet. 110, 124 (1828). At least for actions in state court, as to which there could be no constitutional reason to look to the effect on the State, see Edelman v. Jordan, 415 U.S. 651 (1974), the Court's analysis would support actions for the recovery of chattel and real property against state officials both of which were well known in the 19th century. See Poindexter v. Greenhow, 114 U.S. 270 (1884); United States v. Lee, 106 U.S. 196 (1882)."

NUMEROUS OTHERS, and not even yet mentioning the whole slew of cases derived from the familiar:

Note: In addition, Verizon is also a strong source of support for certain other aspects of our class litigations...