Hashtab can be used to calculate and display hash values from over two dozen popular hashing algorithms like MD5, SHA1, SHA2, RipeMD, HAVAL and Whirlpool.

WinHex is a disk editor and a hex editor useful in data recovery and forensics.

wxHexEditor is an open source cross-platform hex editor written in C++ and wxWidgets. It can work as low-level disk editor too.