Treasury/Savings Bonds

Treasury bond and U.S. Savings bond interest is tax-free only on your state returns but not your federal tax returns.

Treasury bills are short term U.S. obligations of a year or less ( 4 weeks, 13 weeks, 26 weeks and 52 weeks). A Treasury Bond has a maturity of over 10 years. Treasury notes have a maturity of 2, 5 or 10 years,

No. The last E Bonds were issued in 1980 and U.S. Savings bonds have a maturity of 30 years.

Interest that is earned on these savings bonds is taxed to the child, even if the parent paid for the bonds.
The interest earned will be taxable to the child when the bond is redeemed unless an election was made to report the income annually. When the bond is redeemed, the child will receive a 1099-INT form at the end of the year.
This will tell you the amount of interest to report on your child's tax return. If the interest was reported annually over the years, then you will need to separately identify and subtract the previously reported income on Schedule B of the tax return.
Please speak with a local CPA about how to report this and other savings bonds you may not have cashed in yet.

Series "I" bonds are r inflation- indexed bonds that are issued at face value. Interest earned is deferred (not recognized as income) until they are redeemed or mature in 30 years.

Negotiated debt obligations that the U.S. government regularly offers at public auction through the Federal Reserve Bank. Treasury bills, bonds and notes have varying maturities and yields.

A Treasury bill is a negotiable debt obligation issued by the U.S. government, also called a T-bill. Treasury bills mature in one year or less, are exempt from state and local taxes, and range in value from $10,000 to $1 million; they sell at a discount based on current interest rates.