Cleats for Shimano PD 1056 pedals
These pedals will take the old style Look Delta cleats, NOT the Keo-type. The cleats are readily available from Look retailers. You can have them with the same specifications as the Keo cleats, in black, grey and red with 0°, 3° and 6° sideways free rotation.

Be aware though that the pedals have built-in sideways freedom of movement, toggled by the slotted screw at the rear so that it's not a good idea to buy the grey or red type. Probably too much of the good!