Useful Tools

File System Manipulation

• Aaru supports a fairly comprehensive collection of disk image, partition table, and file system formats, and is built with the Microsoft .NET Framework - builds exist, for several operating systems.
• kpartx is a fairly standard command to automatically create loop devices for whole disk images (assuming regular partition table types Linux can understand).
• macFUSE allows you to use FUSE filesystems on macOS.
• OpenVMS ODS-5 file system for Linux is a kernel module, in source form. A TinyCore Linux VM, with it pre-installed is also available.

FUSE File Systems

• CBMFS supports various disk image formats (d64, d71, d81, d80, and d82), from 8-bit Commodore systems
• Atari 8-bit Utils contains ATRFS, which supports Atari DOS 1, Atari DOS 2.0s, Atari DOS 2.5, MyDOS 4.53, SpartaDOS, Atari DOS 3 (read-only), Atari DOS 4 published by Antic (read-only), and LiteDOS volumes, in ATR disk image files.
• FUSEADF supports AmigaOS disk images, and requires ADFLib, to compile.
• FUSE-UFS supports FreeBSD UFSv2 volumes.
• HFS-FUSE supports Apple HFS+ volumes, including resource forks, and extended attributes.
• Acorn ADFS, and DFS implementations, written in Perl. Requires the "Fuse" CPAN module to be installed, to build.
• RetroFUSE supports 5th/6th/7th Edition Research UNIX, 2.9BSD, and 2.11BSD file systems
• PlayStation 2 Memory Card File System implementation, in FUSE
• ratarmount is a FUSE file system, that can mount various archive formats, and allow random access to files, stored within them
• befs-support is a FUSE driver, for the BeOS/Haiku BFS file system (last release is for Ubuntu "Zesty", but can be installed on later versions)

Archive Manipulation

• 7-Zip supports the Windows Imaging format (.WIM) disk images, with LZX compression, as used by Windows 8.1.
• XADMaster supports a fairly comprehensive collection of compression, and archival formats, and can also expand some disk image formats - this seems to be the basis of the "unar" utility, provided for Ubuntu, and some other Linux distributions.
• unshield is a CLI tool, for unpacking various flavours of InstallShield archive.
• jSAVF is a Java-based application, for accessing IBM i (AKA OS/400) save files, under Windows, and Linux

Firmware Image Extraction

• The RandomSHX utility, for Windows will extract the contents of some Motorola P2K (e.g. A835) "UNIX Generated SuperFile" firmware archives - this requires Windows, and does not work with UNC paths.
• The srecord package, under Ubuntu contains a utility, that can convert Motorola S-Record files, into plain binaries: (for example srec_cat C139_V1.0.03.E.m0 -Output C139_V1.0.03.E.bin -Binary).

• BinWalk is extremely useful, for extracting files, and resources out of firmware images, executables, and file system structures.

Binary reverse engineering

• Dependency Walker for understanding Windows program dependencies and what's used by the program, helpful for software archaeology.
• Ghidra is an open-source set of RE tools, including a set of decompilers and disassemblers for most binary formats.

Development tools

• The Amsterdam Compiler Kit is one of the few (mostly) C99 compilers around that can still target a PDP-11 Unix v7 target.
• llvm-cbe is the C backend for LLVM -- it can convert LLVM bytecode into C (useful for compiling modern C++ targeting systems that don't have a functional modern C++ compiler, for example).
• GNUish Project is a port of UNIX standard utilities for DOS with family mode support (useful for replacing equivalent utilities that cannot be ran under OS/2).