Received a new Tektronix AFG1022 function generator, I would like to see if I could output a higher amplitude using a transformer or amplifier
Opamps will be current-limited by internal high-current-detection circuits.

If you need higher voltage and high current, some companies make hybrid (metal can) opamps. 

At one Hertz, you might use a Kepco 4-quadrant power supply, programmable to a variable Vout.