There are cheap kits online that will break out an ATX PSU into banana plugs, but they omit this vital piece. Depending on the ATX power supply being used, they may be unstable without the load.
A benchtop power supply is a key thing to have for any ... The design features banana plugs outputting +12V, -12V, +5V, and +3.3V, with all outputs appropriately fused for safety.