The list can be found here: https://support.apple.com/en-us/HT210770

I don't know how to check for iOS, but macOS is showing 164 trusted certificates for 10.15.7. Via the "Keychain Access.app", select the "System Roots" item, then select all of the items in the right panel, then open the context menu using the two-finger tap method (or control + mouse click)

If there's a better way to check this, feel free to post

Use this command to extract the list of root certificates:

    security find-certificate -a -p > all-certs.pem

You can then dump each certificate:

    split -p "-----BEGIN CERTIFICATE-----" all-certs.pem cert-
    openssl x509 -text -in cert-aa
    openssl x509 -text -in cert-ab
    ...