Per riferimento, ecco l'SQL da \dT (pgAdmin usa lo stesso o simile)
SELECT n.nspname as schema, t.typname as type
FROM pg_type t
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = t.typnamespace
WHERE (t.typrelid = 0 OR (SELECT c.relkind = 'c' FROM pg_catalog.pg_class c WHERE c.oid = t.typrelid))
AND NOT EXISTS(SELECT 1 FROM pg_catalog.pg_type el WHERE el.oid = t.typelem AND el.typarray = t.oid)
AND n.nspname NOT IN ('pg_catalog', 'information_schema');