Recommendation on DBA Tools

Do you have any recommendations on database management tools which helps
DBA to monitor and manage the system, and have the flexibility of adding
add-ons (bring in other tools, like shell scripts, etc.). Something
that would collect and analyze the system performance, monitoring on
space usage, tracking schema changes, generate reports for database,
tables, extents, dbspaces, tracking memory usage, etc., etc., and can be
tailored to send email or page on certain conditions.

We have a lot of individual scripts that would do the above for us. But
we'd like to look into good and maintainable DBA tools that are
available, especially ones that you have direct experience with the
tools.

This would be for AIX and IDS 9.4 (and moving forward).

Thanks in advance for your feedback.

Regards,
Lynn Nguyen