How to acheive something like this….

[Kom Son]

I have a column with different product types. Example: wood, glass, metal, plastic. And I have a drop-down property control to be able to select anyone of of these unique values from the column. Is it possible to be able to create an add an additional value that will allow the user to select all the other values by choosing that value (e.g ALL Products)?

[Gaia Paolini]

You could have a multiple selection list, and select all the value combinations you want. Or you could use a filter.
It really depends on how you wish to use the document property that gets created.