I know some of the screws are meaningful:
S means screw? I'm not sure.
The first 2 numbers usually denote the size.
The last number usually denotes the length.
The next 3 letters denotes the type(buttonhead, hex, nut, standoff, etc.)
I'm not sure about the 1 letter, it is usually S, O, or H.
The last letters indicate the material(SS=Stainless Steel, AL=Aluminium)
025-20: Size (This one is metric, I think)
438: Screw Length
BTN: Head type(Buttonhead)
S: Screw(Instead of Nut)
SS: Material(Stainless Steel)
Some of the other ones are basically just "BAR-1" in essence.