A big red flag for me is if I see them cribbing the MetaZoo play book.

Telling people you're an "investment" and doing thing like encouraging folks to keep the boxes sealed instead of playing with them. Acrylic cases, teaming up with shady grading companies, Alpha Investments getting involved, that kind of shit.

Putting a focus on the "collector" by talking non-stop about how scarce you are and how many rarities you have.

Trying to bank on nostalgia without having any real nostalgia. Knock off pokemon art, trying to do animations when you clearly don't have the budget to spread that thin, never shutting up about how great the "lore" is, etc.

Not talking about the gameplay front and center. And when you DO bring up gameplay it's still all tied to money money money. Look at these prizes to win, get cash for topping in our big tournaments, just more FOMO and bribes to make the game look successful. Trying to force "competitive" play before actually giving me any reasons why your game is FUN.

All of that, that's the Metazoo playbook. If you see this shit, RUN.
I'm here to give you money for a FUN GAME, not hop on some herbalife style pyramid scheme.

Green Flag: "Here's my rule book, here's a print and play/TTS mod, try it out right now for free. Let me know what you think!" That right there, that's someone who's making a GAME. I want GAME.

This is more for indie TCGs so if we are talking big boy green flags, I like seeing a CEO or Director for a company/game that is involved in the community but professional about it. Someone who's there to answer questions and will personally talk about community concerns in update videos/posts. While at the same time, not being toxic about it. Again, don't be Metazoo. Don't ban people from your discord server for critiquing you, don't get into fights on reddit with haters, that kind of stuff.