I have a heavy-duty screw type press for installing cotter pins on olde cottered crank arms on a bicycle. I haven't seen a cottered crank in ten years.

Also, I don't know anyone other than my brother and I who knows how to use a slide rule for mathematical calculations.

Wristwatches? Kids don't use em much. Their phones have the time, if they even care, which many of em don't.

In the kitchen: pressure cookers. Fewer people even do their own cooking, much less know how to use one. Bundt pans. Again, how many people bake their own cakes? I don't even think they sell them anymore.

Saul