This query listed tables that do not have foreign keys, which means that they are not referencing any table or that they are not on the "many" side of FK.
The query below lists something a little different - tables that are not referencing and are not referenced by other tables. Something that can be called as Loner Tables. This diagram illustrates the concept:
select 'No FKs >-' as refs, concat(tab.table_schema, '.', tab.table_name) as 'table', '>- no FKs' as fks from information_schema.tables tab left join information_schema.referential_constraints ref on tab.table_schema = ref.constraint_schema and tab.table_name = ref.table_name left join information_schema.referential_constraints ref_by on tab.table_schema = ref_by.unique_constraint_schema and tab.table_name = ref_by.referenced_table_name where ref.constraint_name is null and ref_by.constraint_name is null and tab.table_type = 'BASE TABLE' and tab.table_schema not in ('mysql', 'information_schema', 'performance_schema', 'sys') -- and tab.table_schema = 'your database name' order by tab.table_schema, tab.table_name;
List of Loner Tables in the Factories database (schema):