Grade Point Average is a singular noun, therefore it requires the singular third person verb form, which is "stands".

[nouns are always third person and may be singular or plural]

So, the correct sentence would be:

"As we all know that  GPA stands for Grade Point Average which may range from 0.0 to 4.0."

If we write the sentence:

"As we all know that GPA stands for Grade Point Average which may range from 0.0to  4.0", then it is necessary to add another clause at the end, for example:

As we all know that GPA stand for Grade Point Average which may range from 0.0to  4.0, then I do not need to explain the meaning any further.