It is not possible to make single stroke TrueType or OpenType fonts, because the glyph shapes consist of a series of closed contours and (most of the time) you need open contours to make a single line font.
When TrueType fonts are advertised as single line fonts, be sure they really are. So ask the font vendor to actually confirm the fonts are real single line engraving fonts, and that they only require the engraver to put one line instead of two. An honest vendor will tell you it uses two...
However there seem to be engraving-specific software that (mis)uses TrueType font technology to draw open contours. Here is a recent discussion about that:
Is it even possible to create a font that is recognizable by Windows applications that consists of only single straight lines? Arcs are also slow to cut on our laser.
Your laser software converts your arc into a series of short lines, so their is no benefit of using a font with lines only.
In a perfect world I need a font that would consist of only single straight attached lines. Possible? Should I spend any more time searching for this?
No, although most people who asked similar questions before usually continue to search for a solution...