I know there is another post with a similar title at the moment, but for me a fantasy SAK is not one that could be put together by a good modder from parts bought today. A Fantasy SAK is an historic piece that could have existed, should have existed, but never did actually get made.
I find the 1950's Tinker a fascinating transitional piece. It has the old Awl with a a cut-out in the scales, the drop-point second blade, visible rivets, and bail. But it has the new "Pat" cap-lifter, and crucially the Phillips screwdriver (at that time squared off with a nail file). That does exist, of course, although I doubt I'll ever own one.
But my Fantasy SAK is a 1950's Super Tinker. With the single-leaf scissors added as a third layer. As far as I can discover, in real life the Super Tinker didn't appear until much later, when all those old features had been replaced by the new reamer, pen-blade, concealed rivets, and key-ring. The closest we can get is the 1950's version of what is now the Climber – which of course doesn't have the essential Phillips.
I'm not suggesting for a minute that I would consider cannibalising a vintage SAK. So the 1950's Super Tinker will remain forever a fantasy.