Adventure, 3D, topview, sideview, use joystick, keyboard, mouse
Battle Cards + digital card collector.
Battlers (map scrolls, fight many opponents).
Balancing, Rotating, and Gravity.
Board Games, Chess, Checkers, Gomuku, Nim, Sorry, Monopoly, Candyland, dice.
Bowling + ball hitting pins.
Casino, either cards, dice, roulette, lotto, etc.
Catch + Release + Avoid.
Celeste Clone (based upon the original).
Classic Arcade, Pac-Man, Space-Invaders, etc.
Click Puzzles + Mysteries, using items or not.
Clickers, Reaction, Cookie.
Coloring Books + Stickers.
Comics.
Creative, Painting and writing.
Dance + Rhythm + Patterns + Recall.
Dating Sim. Virtual dates.
Demos, team animations + music showcasing programming, art, and musical talent.
Dressup, put the clothes on the bunny. ZEP wrote one of these.
Educational, Edutainment.
Exergame, fitness, Dance Aerobics.
Fighters, usually (1 on 1), fixed background graphics. Slug-fest.
Gambling, 5-Card Stud, Poker, Blackjack.
Horror, jumpscare games. Stuff like that.
Just Graphics. Showing off your artistic talent.
Just Music. Showing off your musical prowess.
Simulation, Flight, etc.
Stealth.
Foreign (game is difficult albeit impossible to play for English speaking without translation).
Gacha. Gets its own category.
Game Shows.
Golf. (yes I give this a category to itself as I like it so much). :)
Hidden Object Games.
Idle games. (These almost play themselves).
Jigsaw + Reveal-The-Picture.
Kids + Educational.
Life simulation.
Logical + Brain Games.
Match-3 + Tile-Matching Games.
Mazes + Snakes.
Monster tamer + Battles (Pokemon).
Multigames (where there are small timed games, like 5 seconds each).
Music Loops.
Music Videos.
NSFW Games + Videos (may not apply to Lexaloffle).
Party Games, 2 or more players expected.
Photography, virtual camera + film.
Pick-Your-Own-Path (like the books).
Pinball + Breakout.
Platformers, 3D, Topview, or Sideview.
Programming + Coding. The Fantasy Console within a Fantasy Console.
Puzzles, action or relaxed play.
Quizzes + Tests.
Racing, 3D, topview, sideview, rotating vehicle or not.
Realtime Strategy.
RPGs, action, MORPG, Rogue, turn-based, relaxed play, tactical, 3D, Topview, Sideview, saves game or not.
Runners. (usually sideview, player is constantly running).
Sandbox, Open World, Creative.
Shooters, 3D, topview, sideview, rotating player, uses mouse or not, constant walking or not.
Simulation, Construction + Management.
Social deduction, Clue.
Solitaire, Klondike.
Space Strategy + Selling + Trading.
Sports + Air Hockey. Football, Baseball, Soccer, Basketball, Hockey.
Strategy, 4x, artillery, auto, RTS, RTT, TBS, TBT.
Survival Horror, 3D, topview, or sideview.
Survival Island, limited resources.
Text Adventures.
Time Management + Simulators.
Tower defense, topview or sideview.
Trial & Error + Exploration.
Tribute (give tribute to known game).
Visual Novel.
War Games (Global Thermonuclear War).
Zen + Greeting Cards + Tests + Fakes.
Zelda-Like.