I have been looking at a wide range of different building gaskets lately.
I like specialized EPDM gaskets for most applications.
In some instances a non-specialized, flat, sheet-like gasket could be useful.
I often think of polyethylene foam gaskets for these applications.

How good are polyethylene gaskets?
Do they hold up over time?
Do they retain a “memory” after being compressed for years?
Do they become brittle after a while?