What are all the judo belt colors?

Answer 1

white, red, yellow, orange, green, blue, brown, black

- that is the order of belts for a person aged between 8-16, which are called mon grades. below the age of 8 the grades are called Kai grades, after the age of 16 the grades are called kyu grades.

Answer 2

Technically there are none. You are either a student or an instructor (although Instructor ranks sometimes go Apprentice, Full and Senior).

Some individual clubs use a grading system to facilitate classes and to give students a goal to aim for - as often as not this is to establish a level of proficiency prior to gaining an Instructor based rank.

Some will say there is no ranking system at all, but significantly, Sijo Lee had a number based ranking system - and despite any claims to the contrary the only student of his that holds the top rank is Dan Inosanto