As part of my project of using Linux on my GPD Pocket 2, I wanted to get LibreOffice set up in much the same way I have Pages and Keynote set up for macOS. I needed to get my templates working, including the non-standard font I prefer, MonoRale.
MonoRale is a derivative of the Raleway font, but with the "quirky" numbering and capital "W" fixed into something a little more normal.
I was puzzled because, while MonoRale works fine in macOS, and shows up in Font Book, it did not appear in LibreOffice.
I found an answer hidden away in this community support post:
Type 1 fonts are no longer supported in [LibreOffice]
I looked in Font Book and, sure enough, MonoRale was a Type 1 font.
So how to fix it?
My fix was neither clever nor automated.
MonoRale is a collection of quite a few fonts, and I opened each of the ones I care about in Font Forge, then used the "Generate font" function to export each one as a TrueType font (.ttf).
Some threw some errors, but not enough to stop the font from generating.
Once generated, I imported them into Font Book by double-clicking them. This confirmed the change in type:
I restarted LibreOffice and, sure enough, there they were, ready for use.
(I converted Medium and Regular, as well as Medium Italic, Bold, and Bold Italic, and that should cover my font-style needs.)