Redshift: How to list all users in a group

SELECT usename, groname 
FROM pg_user, pg_group
WHERE pg_user.usesysid = ANY(pg_group.grolist)
AND pg_group.groname in (SELECT DISTINCT pg_group.groname from pg_group);

This will provide the usernames along with the respective groups.

This worked for me:

select usename 
from pg_user , pg_group
where pg_user.usesysid = ANY(pg_group.grolist) and 
      pg_group.groname='<YOUR_GROUP_NAME>';