The Pentax VF Magnifier comes in handy when you want to get critical focus.
As pointed out, these viewfinder accessories are specific to full size or M models. However, an Olympus VariMagnifinder happens to fit all my manual focus cameras of all brands. So if you need a right angle with switchable magnification viewer for your Pentax - or other brands, this is the one to get.
---------- Post added 08-04-18 at 05:01 PM ----------
Another accessory you might find useful for the K1000 - since it doesn't have a self timer, is an external self timer.
You simply screw it into the shutter button, advance the film then set the timer.