The Diversifiers for Global Game Jam is here. The diversifiers are optional challenges that you can try to achieve in addition to creating a game in according to the top secret theme. Here is the list of them copy-pasted from this website. When uploading to the Global Game Jam site you can choose up to 4 different Diversifiers along with your game.
Power of Community - (Sponsored by Mixer) - Make a game where community impacts your game. Players, viewers or streamers can enhance the game, change the outcome, or be a unifying force.
Forgive and Fortify - (Sponsored by iThrive Games) - Create a game that explores how forgiveness strengthens those who practice it. (Forgiveness kits in English, Spanish, Chinese and Arabic)
Always Room for One More - (Sponsored by Origin Access) - Make a game where new players can join at any time.
Use the Source, Luke - (Sponsored by GitHub) - Use one or more open source tools, game engines or libraries in your game (and thank them in in the Technology Notes section on the submission page).
Party Maker - (Sponsored by AirConsole) - Use AirConsole to make a computer game that uses smartphones as controllers (learn how do to this here).
Puzzle design challenge - (Sponsored by Red Bull Mind Gamers and The Tetris Company®) - Make your game around, or inspired by a real world toy you have played with in your lifetime. (For more information, see here)
Language-Independence - (Sponsored by Valve Software) - Create a game that can be understood regardless of which language the player speaks
Let me show you how it's done! - Make a game that is accessible to or represents your own disability, or that of a member of your team, in the way you feel all games should address it.
Celestial - An option to adjust game speed is included
Keep it simple - Make your game playable by people who can use no more than a D-pad plus 2 buttons, with hardware like an Xbox Adaptive Controller in mind.
It is dangerous to go alone, take this! - The game makes use of one or more system/OS accessibility APIs (PC, iOS, Android, and Xbox).
Thomas Wasn't Alone - Use only simple shapes (cubes, triangles, circles, etc.) to represent every single element (characters, HUD, etc.) inside the game.
In Ink - Use only black and white colours in your design. There should be no other colours, not even grey.
Art of Sharing - You and another team must share art assets, without seeing how the other team uses them.
Mind over matter - Add a voice over narration to the gameplay
4′33″ - Your game must draw attention to the natural soundscape of the environment in which the game is being played.
Scale With A Song - Your game must last exactly the length of a single music track.
Assetless - Create all visuals programmatically or in the scene editor, and avoid any importing of image files, sprite sheets, 3D models etc.
Mixed Media - Make a physical game that utilises computer code.
Under the Hood - Make some or all of the code visible in your game.
Super Secret Stash - Feature a hidden room within your game.
This is where we came in, right? - Make a looping game and have the player start at a random point in the storyline.
Bolter is jammed! - Make a game where the main action is obviously missing. (platforming game with no jump, shooter without weapons, etc.).
Sticky Finger - The game begins when you place your finger on the screen, and ends when you take your finger away.
In a webpage - Your gameplay is hidden in a seemingly normal web page.
The Guide I was looking for - Your game has a supplementary guide, using a different medium than the game itself, that players must refer to to beat the game.
Ephemeral - Make a game that can only be played once by each player.
Meanwhile - The story of your game takes place on the backdrop of a seemingly-more significant story. While the real heroes fight evil, what happens elsewhere?
Wanderlust - Your game tries to awaken interest in travel and visiting new places, with a focus on your home town.
Russell’s Teapot - The aim of the game is to prove something unprovable.
20-XIX - Celebrate 2019 by using 19th-century prose and poetry as your narrative inspiration.
The Ancient Folk - The game must include ancient traditions and locations of a community.
Public Domain - Incorporate inspiration from one of the works that became public domain in 2019.
Recycle! - Instead of making a brand new game, start from an existing GGJ game from a previous year, made by someone you don’t know. Improve it and take it in a new direction.
Happy Anniversary - Your game should incorporate 2018's theme (Transmission) as well as 2019's theme.
ADL Identity Framework - Use this framework to explore how to use games and game design to explore identity and better understand yourself and others. (Created by Dr. Karen Schrier and the Anti-Defamation League).
Protect the Oceans - Incorporate elements into your game to raise awareness about marine pollution (Goal number 14 on the UN Sustainable Development Goals).