Delrin plectra from Marc Vogel, in four degrees of stiffness: 1-spot to 4-spot, length 1 cm.
Upper guide lozenges
These are used for virginal and spinets. Photo shows virginals on left (note displaced holes) and spinet on right.
Jack tongues with square holes for leather plectra
The white tongue on the left has the regular hole, for a delrin plectrum. The black tongue has a square hole for a leather plectrum.
The damper felt is supplied in 9mm (approx) strip, 2mm thick, to be cut into 9mm x 9mm squares for use. Felt can also be obtained directly from Hecksher Piano Parts