You can find spare parts for the NeoGeo CD Clicky Pad Repair Kit in the event that pieces are lost or damaged.
Find the full kit here: https://www.laserbear.net/products/neogeo-cd-clicky-pad-repair-kit
This is not compatible with the new pads for the Neo Geo Mini series of systems. It only works with the original pads. It is as of yet untested for the PS1 NeoGeo pad but could possibly work.