There are many balls.
1. Some are blue, and others are yellow.
2. Some are blue, and some are yellow.
3. some are blue, and the others are yellow.
4. some are blue, some are yellow, and some are white.
5. some are blue, others are yellow, and some are white.
6. some are blue, others are yellow, and the others are white.
7. some are blue, some are yellow, and the other is white.
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Are they all grammatical? Would you check them, please. Thank you.
Sentences 1 - 6 are fine as long as you remember to capitalize the first letter of each one.
I'd rephrase #7 a bit, though:
Some are blue, some are yellow, and one is white.