Well, this particular community prohibits asking "what to write", your creativity has to be your own. So I will aim to provide some guidance on how to think about it, instead.
But I agree, the most overused power in fiction is invulnerability / instant healing / immortality. To me, that massively diminishes the character. I'd be pretty courageous too if I could not be harmed in any way. I'm not sure we should even count that as "courage" or "bravery".
In your example of the forgettable man, he doesn't have to be invulnerable at all. He may be completely human and vulnerable. So he has to think strategically how he can use his power to his advantage, for good or evil. He has to be clever.
Same with the kid that can make his drawings come true. As long as that is not too instantaneous,like he can't protect himself from a bullet by drawing a shield in less than a second, and cannot actually draw himself powers like flying, then the kid is vulnerable, and he has to be clever and think strategically.
Another factor may be that his drawings may have unintended consequences. He draws something to get what he wants, like money, but the way it is delivered horrifies him. He drew a picture of himself finding a bag full of money, and he does, but it is the result of a bank robbery gone wrong with people getting hurt. He feels responsible.
So that is that pattern you want to think about. A minor superpower that does NOT confer immunity, or immortality, or freedom from physical harm. One that must be used strategically.
You can base this on senses: Super hearing, super vision, super olfactory senses. Sherlock Holmes key sense is a super memory and super observation of minute details, that is basically how he solves every crime. It is not described as a supernatural power, but clearly is. But Sherlock is just human, he can be kidnapped, beaten up, and emotionally manipulated.
I saw a series some time back, I think it was called "Strange Luck", but the hero's super power was "Luck". If he bought a scratch off, it won. Not big bucks, but $10, $20 whatever. His car gets stolen, and while running a completely different errand, he finds his car across town in the parking lot of the store he's gone to for the first time in his life. Weird stuff like that, but he is not invulnerable at all. Just a normal guy with supernaturally good luck.
So I'd say think in that direction. Super power something we all have occasionally, and give that to a hero that is otherwise a normal person. So they have to use it strategically to be a hero.