My Top 100 Games
https://docs.google.com/spreadsheets/d/1LeFM0SG4xHi62w8BavbzDU2dA_Ya3VUksyuy0v1iPP8/edit?usp=sharing

All HL1 and HL2 Multiplayer Mod Matchmaking Server
https://discord.gg/kr8WWsB

For Checking Steam Sales
https://steamdb.info/sales/

For Checking Lowest Game Prices
https://isthereanydeal.com/

For Checking for Bundles and Deals Internet Wide
https://www.indiegamebundles.com/

Frontend for emulators and games from any source
https://www.launchbox-app.com/

Database of all flash games, making them playable. 150,000 games and more
https://bluemaxima.org/flashpoint/

Searchable archive database of all mobile apps
https://appagg.com/?hl=en

List of current betas and alphas available
https://www.alphabetagamer.com/

Makes 726 games have multiplayer again
https://www.gameranger.com/games/

Largest game database
https://www.mobygames.com/

Benchmarks lots of fun stats for you
https://humanbenchmark.com/dashboard

Concepts section of Giant Bomb, great for finding games you cant remember or games with similar specific mechanics. Also good at answering "What was the first game that did X
https://www.giantbomb.com/concepts/

Reddit page for finding old games you have foggy memory of
https://www.reddit.com/r/tipofmyjoystick/

Wiki for helping you figure out how to get X game running or X game to have widescreen support etc.
https://www.pcgamingwiki.com/wiki/Home

Largest mod database
https://www.moddb.com/

Largest boardgame database, useful for Tabletop Simulator
https://boardgamegeek.com/

Largest Visual Novel Database, very well organized, 41k visual novels
https://vndb.org/

Website for finding alternatives to X program
https://alternativeto.net/

Best and largest video media tracking website
https://simkl.com/

Music player that unifies basically every source
https://nuclear.js.org/

Website giving examples to 1000s of music genres organizing them by similarity to each other algorithmically
https://everynoise.com/

Best digital notes program (better than mindmapping imo)
https://obsidian.md/

Best buying guide for headphones (get a modmic and a nice pair of headphones)
https://www.head-fi.org/articles/headphone-buying-guide.14163/

Crazy huge free to list 100% profit game store. Tons of free stuff
https://itch.io/

How many games can your pc run?
https://www.systemrequirementslab.com/cyri/

Best site for building a new rig or upgrading a current one
https://pcpartpicker.com/

Charts current prices for physical games on all consoles
https://www.pricecharting.com/

Good for finding similar games or just fun
https://tvtropes.org/

Good for reading about TTRPGS
https://1d4chan.org/

Large abandonware database. Nobody holds the copyright anymore so these are free.
http://www.abandonia.com/

Site for finding how long a game is
https://howlongtobeat.com/

Database of game cut and unused content in games
https://tcrf.net/The_Cutting_Room_Floor

Things worth knowing before starting a game
https://www.beforeiplay.com/index.php?title=Category:Games

(More media focused, but still useful) download key art from any steam store page easily
https://steampoacher.com/