I'm gonna talk here about how to go about coming up with ideas. Which sounds really dumb, but I promise it's much more interesting than you think.

Essentially, a lot of people do one of two things. The first option is that they try and come up with something new, no part of which has been done in any way, and get absolutely no ideas, because everything has already been done in some way at some point by someone. There is no such thing as a tropeless work. Hell, even trying to make one is a trope of its own. The other thing people do is just fully rip something someone else did. That's no good either. You have to strike a happy medium a lot of people aren't comfortable with.

So basically, there are no new ideas on the planet. But there are new ways to use the existing ideas, and new combinations of them. The best way to make a game that you, and hopefully other people with similar tastes to you, will like, is to take something you already find memorable for some reason, and make it your own.

Things that are maybe memorable:
-An element from a piece of media you really liked for whatever reason. Good design, fascinating concept, etc. If it sticks out, it's a good choice.
-A particular element you very distinctly DIDN'T like, in a memorable fashion. It's very satisfying to take something you despise and use your fancy woo-woo brain magic to turn it into something you actively enjoy.
-Something that could've worked, but was badly done. A let-down of cosmic proportions. It was just poorly executed, it was scrapped, it was changed, it was underused, anything you were excited about and then disappointed by.

All of these things are great places to find inspiration. I really enjoy thinking back to memorable games from my childhood, or web series I used to watch, and the like, and writing down the first things that come to me the clearest. Once you have a good list of them, start thinking of ways to change them, make them better, make them your own, while still keeping the parts that gave them their memorability.

For a funny gumball game example, let's take Stab the Carpet Shark. Stab's first idea of a shark fin stemmed from a scrapped concept from a fangame I was helping a friend with, called Baldi's Fun Zoo. That game is still a thing, go check it out. Basically, my idea was for a guy that appeared as a stock image of a washing machine with a shark fin on top for some reason, which would patrol back and forth in a bouncy-looking fashion while making hellish screeching noises. The washing machine part was pretty much unchanged as the basis for Spins, but the shark fin was something I felt bad not using. So, I thought "How can I make a creature that appears as a shark fin, which is both creepy and bizarre?" And so Stab was born. He just kinda wanders around aimlessly, occasionally changing between patterns, creating the effect of a very lackadaisical worldview. If you touch him, you die instantly, but he never intentionally approaches you, so if you don't get too close, you're not really in any danger. Also, he's orange, because it's a bright and moderately unnatural color for a shark fin to be. His wake was inspired by the Soul Sand from Minecraft and the Mattermouths from Super Mario Galaxy 2. In SMG2, Mattermouths are ghostly skulls that eat through the carpet floor, leaving a long hole behind them that resets a little after, making a wake of sorts. You probably know what Soul Sand is already. I combined those, creating Stab's wake, a brown, low-pixel-count pattern that resembles exaggerated screaming faces frozen in time. If you walk on it, you're greatly slowed down until you stop touching it. Originally, I had no idea what I was gonna do for the wake, I just kinda drew something until I liked it. With that, I made the black comedy lore of Stab. He just kinda schmooves around, very kind, uncaring, laid-back. Unfortunately, anyone who touches his fin dies a horrible death and has their soul permanently trapped in his wake. In the final game, when stepping on the wake, you'll be able to hear the anguished screams of the tortured souls contained within echoing around you. Entertainingly, Stab has no idea of any of this, and is just blissfully unaware (unlike his cousin Shank). The song that may play when near him is "stella", a slow and happy-sounding chiptune track that fits with his carefree attitude. You can go listen to it on the gamepage.

All of this falls together to make a fun, creative idea that takes things directly from a ton of different sources, but feels completely new and unique to the game with the way it's done. I consider this to be a great example of how taking things you know and love (or hate, of course) and adding bits from other things, taking out the bits you don't like and adding new ones you do, is pretty much the best and most fun way to design games.