Why have certain symbols and notations gained general acceptance, while others fell into oblivion? And why did mathematicians happily adopt TeX as a standard, while they hardly ever used MF (or other tools) to develop new notations? In this presentation I will give quality criteria for mathematical symbols. I will show many unknown, little-known or little-used notations, some of which deserve to be much more widely used. Also I will show new symbols and ideas for new notations, especially for some well known notions which lack a good notation (e.g., gcd and lcm, Stirling numbers, and more).