The MySQL distribution provides several tools for database developers and administrators, but they don't always work everywhere. Fortunately, the worldwide MySQL community has produced plenty of useful tools. Baron Schwartz surveys the possibilities and offers suggestions for what you should use.
At some point I have used most of these tools:
Tools to Monitor Queries and Transactions
=> mytop - Old but still good tool
=> innotop - MySQL and InnoDB monitor
Tools to Monitor a MySQL Server
=> mysqlreport - Easy to understand MySQL status report perl script
See list of Open Tools for MySQL Administrators list [oreillynet.com].