One ring transformer (2x 18V, 50VA, Reichelt Order No. RKT 5018)
Two volt and two ampere meters (primary use is to make the PSU look impressive, secondary use is to check if everything is OK - could be solved in a cheaper way, each meter is about 5 EUR)
A heavy rocker switch (also to make the PSU look cool)
Two white LEDs for indicating the +-15V lines
A circuit distribution board to connect the volt/ampere meters to the circuit
A power distribution board to connect the modules to