Michael Chare brought next idea :
What soft material would be OK in a domestic oven used for cooking.

I want something that I could attach to the ends of the telescopic rails to
stop them damaging the glass door if they have not been pushed in properly
when the door is closed.

You can buy a soft silicon rubber designed to be fitted to oven racks,
to save burning yourself when making skin contact with the hot oven
racks. Would that work?