IMAP Folder Manager was created to manage IMAP folders for large user bases. It can list, create, delete, and rename folders, count messages in a folder, move or copy all the messages from one folder to another, and empty a folder. It supports PROXYAUTH for easy user management and has a simple but powerful argument interface, able to do things like "create folder2, move messages from folder1 to folder2, and delete folder1" in a single compact line.
Libpwmd provides an API for applications needing to communicate with PWMD (Password Manager Daemon). It is thread safe. It can connect to a remote pwmd server over an SSH channel or via TLS using a client certificate as authentication. It can use a pinentry program to prompt for a passphrase when needed. It supports secure memory management. It includes a command line client with a shell-like interface that can also read a Pwmd protocol command from standard input.
NOTE is a small console program that allows you to manage notes similar to programs like "knotes" from the command line. It supports different database backends for storage, and includes a DBI-based MySQL module and another module that uses a binary file for storage and a DBM module.
Genius is an arbitrary precision integer and multiple precision floating point calculator. It includes its own programming language similar in some aspects to C, bc, or Pascal. It can deal with rational numbers and complex numbers. It has matrix support as well. It uses the gmp library so it is very fast for calculations of large numbers. It has a command line and a GNOME interface. The GNOME interface supports plotting functions and 3D surfaces.