Check out Aldi for door stoppers.

They weigh approx 1kg, supposedly stainless steel but a weak magnet sticks very well, come in 2 sizes, approx 30mm high with a slight dome in the middle or approx 75mm high and flat topped, price $4.99 each, both types have a rubber foot.

I bought 4 of the 75mm high ones, stuck some grippy rubber to the top and they work well in conjunction with my bench jacks or on their own.

https://www.woodworkforums.com/f44/el...-jacks-107412/

Regards,
Bob