This list includes SQL reserved words – aka SQL reserved keywords,[1][2] as the SQL:2023 specifies and some RDBMSs have added.
It may depend on the database vendor if the keyword is non-reserved or reserved, or neither, i.e. not (yet) supported.
Most databases support INDEX, which the SQL standards do not define.
Databases such as PostgreSQL have extensions like ANALYZE (a reserved keyword), and depending also, PostgreSQL supports it as a synonym, some others only support the American spelling.
SQL standards have added many keywords over time.