In no particular order...
LIPEMCO!, stargood and other translation projects, tools, odds and ends... and much more. Beautiful website design.
Kingdom Hearts II Final Mix (PS2)
Crazycatz00 English patch.
Monster Hunter 2 DOS (PS2)
BREAK ARTS English patch. Additionally, check out GReinoso96's MH2Plus Github, which allows you to patch in PSP controls to DOS.
Roms/emulators and more.
Prepatched roms, usually a good spot to see the newest translations and romhacks at a glance.
When all else fails...
Collect achievements without the pricetag of modern console gaming. Sets are designed and curated with love, offering thoughtful challenges. There are also subsets: like a low level, no junctioning set for Final Fantasy 8 or Professor Oak challenges in Pokemon titles. There's a lot of fun to be had here re-exploring your favorite retro titles.
My PS1 emulator of choice.
My PS2 emulator of choice. You can have a pink theme. Thank you.
PS2 Cover Downloader
For PCSX2. Allows you to download covers to the emulator to make it clean and sparkling.
Useful for everything else. The default UI is really annoying and ugly. Go into the settings and change it to the XMB layout. Thank me later.
Play arcade games online with strangers or with friends. I strongly recommend CAVE games.
A valuable hub for hacks, translations and much more.
Breathe new life into your favorite N64 games.
Flipnote revival project.
Brings back WiiConnect24 services to your Nintendo Wii.
Wiimmfi Project replicates the (defunct) Nintendo Wi-Fi Connection (WFC) service, allowing you to play games online (NDS, Wii) with your friends again.
Resurects defunct channels to the Nintendo Wii (including ones not released in North America, like Wii Room).
A customizable gamertag for the Wii/WiiU that update whenever you play.
My favorite homebrew application on the Nintendo Wii.
A mod for Mariokart Wii that lets you do wild things. Very active online community as well, which is very fun.
Project Plus / Project M
A mod for Super Smash Bros. Brawl with extensive features and a very active community.
3DS Preservation Project.
Hosts a bunch of files, I mention it though for its WiiWare collection.
Extensive visual novel database.
The Asenheim Project
Play retro visual novels in your browser.
(Mostly) PC Based
A program for playing tabletop card games over a network.
Phantasy Star Online: Blue Burst ULTIMA Server
Free fan server run by a motivated team.
Doujin PC games (music, and more).
Museum of abandonware.
Even more abandonware!
Mods for many different kinds of videogames.
Annoying to use, but hosts a good deal of mods. I've used it primarily for Stardew Valley mods.
TempleOS game developer.
A revitalization project for the Japanese 3D MMO social chat, Sapari.
My favorite gaming related website to date. I just love this thing, if I can use it while I'm playing a game I will.
Absolutely gorgeous and it makes me feel nostalgic but in a really precious way.
A wonderful guide on all things Tamagotchi.
I just love to browse this site, it's beautiful.
Still hosts good old text based, ASCII art game guides for retro titles.
Retro videogame magazine library.
Xenogears and Xenosaga Study Guide
A wealth of information on the topic of Xenogears and Xenosaga. I've gotten a lot of use out of it!
Translated materials, scans, articles and interviews all on the topic of Final Fantasy VII.
Final Fantasy VII news, information, scanlations, and much more.
Retro gaming news and information on obtaining ideal picture quality from your hardware.
Hub for PSP/PS3/PsVita homebrew (among other things).
PsVita "jailbreaker". Has many other projects but that's what I recognize them for primarily.
Disc preservation project.
Beautiful library on videogaming.
There is always super interesting, niche, and/or useful information and resources here.
A website designed to help you keep track of your gaming backlog.
3D, open-source Sonic fangame. I strongly recommend SRB2kart.
A useful resource to keep track of price trends for videogames. I use this a lot to determine when best to buy a game I'm hunting or when to sell and how much to sell it for. Very handy to have whenever you go to a used game store or something.
Database of console variations.
Videogame commercials and advertisements library.
Hub for all things Phantasy Star.
Monster Hunter Old School Forums
Discussions and resources regarding older Monster Hunter games.
A database of music from the Super Nintendo.
A library of videogame OSTs. In the last couple years, they have made it so you have to pay to be able to download entire albums or something along those lines. Maybe it's a cap, I can't rememember. This is annoying but ultimately this is the best resource I have found to gather tracks with correct metadata online.
An archive of videogame remix songs.
Game developer translations.