Super Saiyan is one of the most significant things to come out of the Dragon Ball franchise. It was already awe-inspiring when Goku realized the legend in his climactic battle with Frieza in Dragon Ball Z. However, once the Cell Saga opened up the idea of new levels of Super Saiyan, that started a trend nobody could have expected. Super Saiyans 2 and 3 are remembered as the primary forms to come out of that ideology, but they were only scratching the surface.
Source：https://www.cbr.com/dragon-ball-super-saiyan-forms-explained-anime/
