The query below lists all tables that do not have foreign keys.

See also:
Query
select tab.table_schema as database_name,
       tab.table_name,
       '>- no FKs' as foreign_keys
from information_schema.tables tab
left join information_schema.table_constraints fks
          on fks.table_schema = tab.table_schema
          and fks.table_name = tab.table_name
          and fks.constraint_type = 'FOREIGN KEY'
where tab.table_type = 'BASE TABLE'
      and tab.table_schema not in ('mysql', 'information_schema',
                                   'performance_schema', 'sys')
      and fks.table_name is null
     -- and tab.table_schema = 'your database name'
order by tab.table_schema,
         tab.table_name;
Note: if you need the information for a specific database (schema), then uncomment the table_schema line and provide your database name.
Columns
- database_name - name of the database (schema)
- table_name - name of the table
- foreign_keys - symbol indicating the lack of FKs
Rows
- One row: represents one table that does not have a foreign key
- Scope of rows: all tables in a database (schema) that do not have foreign keys (do not refer to other tables)
- Ordered by: table name
Sample results

 
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                     
                                                                 
                                                             
                                                             
                                                             
                                                             
                                                                 
                                                             
                                                             
                                                                 
                                                             
                                                             
                                                             
                                                             Bart Gawrych
                                                                        Bart Gawrych
                                 MariaDB
                                                                MariaDB
                                 SQL Server
                                                                                                SQL Server
                                             Azure SQL Database
                                                                                                Azure SQL Database
                                             Oracle database
                                                                                                Oracle database
                                             Snowflake
                                                                                                Snowflake
                                             Amazon Redshift
                                                                                                Amazon Redshift
                                             IBM Db2
                                                                                                IBM Db2
                                             Teradata
                                                                                                Teradata
                                             Vertica
                                                                                                Vertica
                                             PostgreSQL
                                                                                                PostgreSQL
                                             MySQL
                                                                                                MySQL