nes

FamiStudio is a simple music editor for the Nintendo Entertainment System or Famicom. It is targeted at both chiptune artists and NES homebrewers.

Multi-system emulator (NES, SNES, GB, GBA, PCE, SMS/GG, WS) for Windows, Linux and macOS.

Mesen is a cross-platform (Windows & Linux) NES/Famicom emulator built in C++ and C#.

A program that creates Animal Crossing NES ROM save files for Animal Crossing to load

FCEUX is a Nintendo Entertainment System (NES), Famicom, Famicom Disk System (FDS), and Dendy emulator. It supports NTSC (USA/JPN), PAL (European), and NTSC-PAL Hybrid modes. It supports both Windows and SDL versions for cross compatibility.