I was a bit bored, and came up with this conjecture - Euler’s unsolvability conjecture. If a problem that euler has tried to solve, but he could not, then that problem is unsolvable (by unolvable, either a analytic closed form solution does not exist, or if he was trying to find a polynomial solution to np problem). I know this is not a proper conjecture/or proper maths, but this community is closest to what i want to say.