In Accounting "Contra Entry" Used to reverse between Cash and Bank only? If "No" then why itis in Tally only for Cash and Bank Transaction only.

Yes, contra voucher is used only to post cash to bank and reverse entries.

Contra entries are used in accounts for Recording transactions of Bank and Cash. 

Example Cash deposited to Bank, Cash withdrawn from Bank, transfer of funds from one bank to another bank.

As per the Accounting Principles, a Contra entry is a transaction involving transfer of one cash/ bank account between another Cash/Bank AC.