Problems with "Sign in with" field

Thanks @steph.giles! The list I see shows, in addition to the supported sign in with providers, accounts that are not supported providers, such as for a shoe store, a health insurance provider, and some forums that all use regular email/password combinations for sign-in, an ORCID account (but not a second ORCID account I manage), as well as some logins that themselves use a supported sign in with provider. I can't tell why these other accounts would show up and why then not all such accounts would show up, just a small subset.