You can use the following query to get the info from one database.
SELECT nspname AS schema_name, c.relname AS toast_table_name, c.oid AS toast_table_oid, r.relname AS main_table_name FROM pg_class c JOIN pg_namespace n ON n.oid = c.relnamespace LEFTJOIN pg_class r ON r.reltoastrelid = c.oid WHERE c.relkind ='t';
But to get info from all the databases then you need to write a shell script which will first get all the databases and then run the above query on the all returned databases.
