Maatkit is a collection of essential command-line utilities for MySQL
Mycli is a command line interface for MySQL, MariaDB, and Percona with auto-completion and syntax highlighting.
a tool that splits a mysqldump into several files (chunks), one file per table
OurDelta produces enhanced builds for MySQL, with OurDelta and third-party patches, for common production platforms.
Flipper is a tool for managing pairs of MySQL servers replicating to each other (commonly known as master-master replication or dual-master replication)