Stop the Attack on Local Taxpayers Act of 2021 or the SALT Act This bill repeals the limitation on the deductibility of state and local taxes during 2018-2025. It also increases from $250 to $1,000 the tax deduction for certain expenses of elementary and secondary school teachers and allows a deduction from gross income (above-the-line) for certain training and uniform expenses of first responders (i.e., individuals who are law enforcement officers, firefighters, paramedics, or emergency medical technicians for at least 1,000 hours during a taxable year). The bill expands individual income tax brackets and increases the top income tax rate for individual taxpayers to 39.6%.