Not unless the word "say" is a colloquial noun meaning "word" or "contention" or speech.
The word says is a verb form, third-person singular present tense, e.g. He says he feels fine.
The only way that you could use say's (as a contraction of say is) would be in constructions such as:
"His say's not enough to convict the killer." meaning "His word is not enough."
"Your say's over, and it's time to vote." meaning "You have had your chance to speak."
The quotation in which this contraction appears is from Act II Scene 3. Macbeth says, "who could refrain,/ That had a heart to love, and in that heart/ Courage to make's love known?" In this particular quotation, the contraction is of "make his".
There is no contraction for were you. There is no contraction for you were.There is a contraction for "you are" (you're).
There is no contraction for "its not."There is a contraction for "it is" (it's).There is a contraction for "is not" (isn't).
He's already IS a contraction. It is a contraction of he is.
It's is the contraction of it has and it is.
There is no contraction. There is a contraction doesn't which means "does not."
There is no contraction for I was. There is a contraction for I am (I'm) and for I have (I've).
There is no contraction. The contraction we're means "we are."
The contraction for he will is He'll
We're is a contraction of we are.
"They've" is the contraction for 'they' and 'have'.
The grammatical contraction for "have not" is "haven't."