Here's a quick list of some of the major ones:
JPMorgan Chase, Bank of America, Wells Fargo, Citibank, U.S. Bank, PNC, Capital One, Truist, TD Bank, Charles Schwab, Vanguard, Marcus by Goldman Sachs, Goldman Sachs Private Wealth, Morgan Stanley, E*TRADE, USAA, M&T, RBC, American Express, Fifth Third, Citizens, KeyBank, Huntington, Ally, Discover, BMO
When I connect something to Chase with Plaid it is clearly a cooperative system with an OAuth-like permission dialog, and the Chase side even mentions they're tokenizing the account numbers so Plaid can't see them.
When I connect to the little bank down the street I just get a username/password dialog. Their web banking system is so primitive I'm pretty sure Plaid is just scraping it. When they introduced 2FA, Plaid became quite flaky.
Quite the opposite in the case of TD Bank. They sued Plaid in 2020. “The bank said in the court filings that the Plaid interface dupes consumers into believing they are entering personal information into TD Bank’s trusted platform.” (They settled in 2021 without explaining the terms of settlement.)
https://financialpost.com/news/fp-street/td-bank-files-lawsu...
https://www.prnewswire.com/news-releases/td-bank-group-and-p...