This is for creativity.

Write down all games, cartoons, comics/manga/art, movies, etc that you know well enough to imagine.

Now just, imagine a scenario, don't be picky, just improvise and roll with it.

Now repeat for each thing in your list.

Go back, and look up each thing to see how well you got the details for their body language, art style, appearance, personality, etc.

Now this is for processing power.

Imagine having a miniature floating walking person with your invisible telekinesis of your mind. Now imagine anything else verbing also miniature, with it in your mind, rotate them around a third thing verbing. Its best if each verb uses a different part of the brain, like one is reading outloud, another walking, another knitting, another juggling, or even a cat playing with a ball of yarn etc.

The goal is to try and imagine as much at once as possible, to exercise your working memory. If you are trying to handle too much at once, take one away periodically. If you can remember them all, try noting them each as regularly as possible for more detail per second or such. The more complex the movements and the more detailed and specific the movements the slower or more difficult this will be. I mean you could always make it like peripheral vision and combine everything vaguely then make it easier, but thats not the point, the point is to try and do better. Then just keep adding more, don't expect vastly rapid improvement, but do expect it to get easier over time.

Now here is the catch, over time your habits form faster and faster as the neurons connections get closer n closer, til its habit and its muscle memory essentially. So, at that point, it might not exercise your working memory as much anymore, like, you skim over the details.

So you gotta change the activities of each floating thing semi-regularly, or rotate it in other directions.

Um, and those are small, you don't have to do small things, you could do giant things, as long as they are about the same size and all in your vision, so if you want imagine you are in the sky perhaps, otherwise the background of your daydream environment might be less noticeable then you might form a bad habit of not noticing your surroundings or something (idk) but thats another way to mix it up, you can do it each day in a different art style, or different location you hover over, different planet, lighting, etc.

Then if you can do this stuff easily while on a treadmill perhaps, or while also planning for the day ahead, then you are getting the hang of it and can make it more challenging. But while on a treadmill helps to exercise your multitasking even more, you could also chew gum at the same time you are on a treadmill for instance. Or chewing gum, treadmilling, while playing with something in your hands like a pen or such.

Now this next exercise is math, but not math.

So you imagine anything, a strawberry perhaps while floating over egyptian pyramids. Imagine it double, two strawberries, quadruple, 8. Seeing it in detail between each math to make sure you are processing it correctly instead of assuming. Just doubling alone is a good enough start for that, tripling each time might be a hassle much faster.

2 4 8 16 32 64 128 256 512 1024. Each day try to imagine one further. 2048. 4096.
Do not stack them cuz then it gets more ridiculous to guess how much you have, so imagine baskets of specific quantities of each perhaps, to make it easier. So you have a basket with 8, then just double the basket, its kinda cheating but not, but double checking more than a handful of the item is going to be ridiculous so you need a different pattern recognition going to simplify it. Or you could have them float like a cube, with exactly 27 (3x3x3) strawberries if you do tripling, then triple counting is much easier.

Lemme know what you think or if you have your own ideas or if you wanna try it.