Assemblers

program that turns assembly language into machine code

assembler and disassembler for the Intel x86 architecture

GNU assembler, part of binutils

FASM (flat assembler) is an assembler for x86 processors. It supports Intel-style assembly language on the IA-32 and x86-64 computer architectures. It claims high speed, size optimizations, operating system (OS) portability, and macro abilities. It is a low-level assembler and intentionally uses very few command-line options. It is free and open-source software.

x86 assembler that uses the Intel syntax for MS-DOS and Microsoft Windows

computer assembler developed by Borland

high-level assembly language

Wikimedia list article

DOS, OS/2 and 32-bit Microsoft Windows command

assembler in Unix-like operating systems