ImHex

ImHex is a feature-rich Hex Editor aimed towards Reverse Engineers working with foreign data formats, malware, executables and raw memory.
Besides all the features a common Hex Editor has, ImHex also features a custom scripting language used to declare and dissect data structures, support for running YARA rules, a node-based graphical data pre-processor and support for various data sources such as files, raw disks or GDB Servers.