Not only are there default Lightsaber Colors we now know that they can be changed as shown with Ahsoka’s Lightsabers. This also explains why Anakin’s Lightsaber was Blue despite going more Dark each second(which was what turned Ezra’s Lightsaber Green): He hid the Color Change for personal aesthetics.
The Lightsabers in R2-D2 were likely Anakin’s experiments in Lightsaber Color Change naturally which is why they were each of various shades of Blue and Green.
When a Jedi turns to the Dark Side their Lightsaber changes to match the color of the Nightsisters’ Magics: Green.
The fact that a Jedi that is good at tech can change a Lightsaber shows how easy it was for the Jedi to be blind to their falls to the Dark Side of the Force since they didn’t know that Green was a Dark Side color.
The Light Side Colors are Blue(Order), White(Compassion) and Yellow(Serenity). The Dark Side Colors are Green(Fear), Red(Pain/Anger) and Black(Aggression).
We’ve seen blends of Blue & Green(half the Jedi in the Jedi Order), Blue & Red(Mace Windu), White & Black(the Darksaber created by a Mandalorian Jedi) and Blue & Black(seen in the Covers for the High Republic).
The Non-Kyber Lightsaber Colors(that get their Blades from something other than a Kyber Crystal) are Orange and Electrified Yellow(https://starwars.fandom.com/wiki/Electrified_laser_blade?file=ElectrifiedLaserBlades-TB.png)…