Tools

Compilers, Assemblers, and Toolchains

 * PVSnesLib - SNES framework toolchain and C compiler
 * cc65 - 6502/65816 assembler, and 6502 C compiler
 * WLA-DX - multi-platform assembler, includes SNES 65816 and SPC-700
 * asar - patch-oriented SNES assembler
 * bass - Near's table-based assembler with support for for SNES 65816 and SPC-700
 * Free SNES Assembler - lightweight SNES assembler by Bisqwit
 * xkas-plus - multi-architecture assembler, includes SNES 65816 and SPC-700
 * TASM - Telemark Assembler for DOS, freeware table-based supporting several processors (WIN64 build, SPC700 table definition)

Debugging

 * Mesen-S
 * bsnes-plus
 * no$sns

Sound

 * SNES GSS - tracker and sound/music driver

Web tools

 * SnesInstructionCycleTool - calculates CPU cycles and master clock cycles under different conditions
 * Mode7Preview - allows you to specify formulas for Mode 7 registers per-scanline and view the result
 * Telinc1 Mode 7 Simulator - allows you to adjust the Mode 7 register parameters and see the result, and source frustum