MySQL has a variety of other storage engines either for experimental or specialized use cases. Some of them are listed here:

• The archive engine: Archive is not a transactional storage engine, but simply optimized for high-speed inserting and compressed storage. This supports only INSERT and SELECT queries, and it does not support indexes until MySQL 5.1. It's much more IO efficient compared to MyISAM. Archive tables are thus best for logging and data acquisition.
• The CSV engine: The CSV plugin can use comma-separated values (CSV) files as tables. However, indexes on the files are not supported. CSV tables are thus useful as a data interchange format, since the tables can be constructed from CSV files automatically, while also allowing access to the files from other programs.
• The memory engine: This plugin (formerly called HEAP tables) stores data in memory and thus is good when you need fast access to data, and durability after restart is not that important. They are useful as lookup/map tables, but generally it's advisable to use key-value stores for these use cases.