Here are some options to double your money: Tax-free Bonds. Initially tax- free bonds were issued only in specific periods. ... Kisan Vikas Patra (KVP) ... Corporate Deposits/Non-Convertible Debentures (NCD) ... National Savings Certificates. ... Bank Fixed Deposits. ... Public Provident Fund (PPF) ... Mutual Funds (MFs) ... Gold ETFs. More items...