A technique that I would love to try on my next stool is blind- or fox-wedged tenons. They are tenons that are wedged during install by pushing a partially-inserted wedge against the inside of the mortice. It then expands and the joint becomes permanent.
Here is a
video where Paul Sellers demonstrates a fox-wedged tenon. He does use glue but I would advocate simply ignoring that! People often use glue when wedging tenons or tool handles but, in my
experience, the glue is simply not needed and can even make repairs more difficult (particularly to axe handles which may become loose seasonally).