fkchk is a MySQL InnoDB/XtraDB foreign key checker and repairer. It is useful if you suspect that your database's foreign keys may be broken, or if you disable foreign key checks and now want to be sure that the data is consistent. It is also useful if you have suffered a performance hit and want to check the consistency of foreign keys to verify that they're not the reason. It can attempt to repair any issues it finds, but this option should not be used and is only implemented for testing purposes.
Spiderinabox provides an out-of-the-box solution for secure browsing on Mac systems. It includes a basic preconfigured installation of OpenBSD prepared as a VirtualBox image loaded with Firefox and a few scripts and programs to launch it and invoke Firefox over a secure connection. The visualization of Firefox is done on the OS X side using XQuartz, so you don't need to exit your working environment and switch between OS X and OpenBSD. Firefox runs encapsulated in OpenBSD and doesn't have access to OS X in any way.
Valentina Studio is a GUI manager for local files of Valentina DB, SQLite, MySQL, PostgreSQL, and Valentina DB Server. It can edit and browse schemas and records, do SQL queries using a smart SQL editor with autocompletion, export/import into different formats, do SQL dumps, and draw diagrams using reverse engineering.
garith is a game similar in spirit to BSD's "arithmetic" or TuxMath. The game asks you to perform a simple arithmetic operation within a certain time frame. It improves your skills by stressing the operations you get more frequently wrong or that longer to answer. The statistics are saved/restored across games, so that each game is tuned for your current arithmetic abilities.