Heres the latest release of an emulator that supports lots of Nintendo and Sega Systems:

higan is a multi-system emulator that began development on 2014-10-14.

It currently supports the following systems:
Nintendo Famicom
Nintendo Super Famicom
Nintendo Game Boy
Nintendo Game Boy Color
Nintendo Game Boy Advance
Sega Master System
Sega Game Gear
Sega Mega Drive
NEC PC Engine
NEC SuperGrafx
Bandai WonderSwan
Bandai WonderSwan Color

higan also supports the following Super Famicom subsystems:
Super Game Boy
BS-X Satellaview
Sufami Turbo

Minimum System Requirements:
Intel Core-series processor
OpenGL 3.2-capable graphics card
Windows XP+, OS X 10.7+, Linux 3.2+ or FreeBSD 10.0+

With this release, PC Engine, Master System, Game Gear, Mega Drive and the newly added SuperGrafx support are now quite usable! They're far from the best emulators for these systems, but with many bugfixes, full sound emulation, and save state support ... many games are now fully playable with decent accuracy.

The Game Boy Advance emulation is also now substantially improved with vastly improved sound quality and a new dot-based PPU renderer. With that change, every single component in higan is now cycle-based. Regrettably, these changes do carry a ~20% performance penalty compared to GBA emulation in v102.

Changelog: (2017-06-21)
added SuperGrafx emulation
improved audio band-pass filtering for all emulated systems
screen rotation is now a hotkey; automatically rotates control bindings
screen rotation now supported on the Game Boy Advance as well (used by a small number of games)
massive improvements to Mega Drive emulation
massive code cleanups and rewrites to many CPU emulation cores (MOS6502, WDC65816, SPC700, etc)
Famicom, Master System, Mega Drive: added PAL emulation support
PC Engine, SuperGrafx, Master System, Game Gear, Mega Drive: added save state support
PC Engine, SuperGrafx: added PSG sound emulation
Master System, Game Gear: added PSG sound emulation
Mega Drive: added Z80 APU emulation [with help from Cydrak]
Mega Drive: added PSG sound emulation
Mega Drive: added YM2612 sound emulation [Cydrak]
Super Famicom: fixed Super Game Boy emulation
PC Engine: added save RAM support (using per-game PCE-CD backup RAM)
Game Boy Advance: substantial improvements to audio emulation quality
Game Boy Advance: convert scanline-based PPU renderer to a dot-based renderer
Game Boy Advance: properly initialize CPU state (fixes Classic NES Series games)
Game Boy Advance: MUL timing corrected [Jonas Quinn]
Mega Drive: emulate special mappers for Phantasy Star IV, Super Street Fighter II, etc.
Super Famicom: use darker luma for INIDISP=0 (large improvement to Final Fantasy III opening)
Super Famicom: fixed bugs in SMP OR1,AND1 instructions
cheat code database regrettably removed from official releases; will be made available separately

This changelog is a summary of major changes. For a detailed list of all changes, which spans several pages, please see the higan Gitlab repository.