Free Portable Hex Editors
Frhed is a Free Hex Editor (also known as a Binary File Editor) for Windows. It is lightweight, open source, and designed for editing binary files quickly and efficiently. A portable version is also available, making it easy to carry on a USB flash drive for use on the go.
HEX-ED is a Free Portable Hex Editor that is both small and efficient. It was originally used by it's author to modify programs written in assembler. Hex-Ed began life decades ago, as a BASIC program compiled in BASCOM under CP/M. The author has since recompiled Hex-ED in Visual C for Windows, first 16 bits and now 32 bits.
Hexplorer is a free portable Hex Editor that is very similar to HxD. As the name implies, this free hex reader and binary file editor can be used to explore and edit binary hexadecimal files.
HxD is a lightweight, free and portable hex editor utility for editing files, drives, and memory at the byte level. This versatile freeware tool is trusted by programmers, reverse engineers, and technical users for viewing and modifying raw data structures in a clean, easy to use IDE.