A red laser is the lowest risk and were the first developed.
The green laser is mostly used in attacks. A green laser is about 60 times brighter than red. It can cause flash blindness at lower levels but is mostly a distraction particularly at critical phases of flight.
A blue laser is not legally available and should be avoided at all costs. At close range it can cause irreversible retina damage. It can burn through clothes and skin!
Well that's what a brief I received told me!