FiraSans VS fantasque-sans

I think you might be taking the wrong approach here. You're right, some devices (anything that isn't Mac or Windows) don't have the "base 14" fonts available, but they don't need to if you just use embedded fonts in the generated PDFs. Any OFL-licensed font can be freely distributed with your app, and can be embedded in the PDFs generated by your app. Like all licenses you should read it yourself and not take my word for it, of course.

Fira Sans

A very pleasant detail with regards these typefaces, they are licensed under the Open Font Licence and are free (as in speech as well as in beer) to use.

Many free fonts on Google Fonts are available under the [Open Font License (OFL)](https://scripts.sil.org/OFL) and [Apache License](https://www.apache.org/licenses/LICENSE-2.0.txt). The OFL is very short and has some clear guidance on how the fonts can be used, so maybe that would be worth looking into!

Or should I better limit myself to use in CC BY PDFs only fonts that themselves can be freely redistributed, reused, remixed, such as those available under the SIL Open Font License?

This Font Software is licensed under the SIL Open Font License, Version 1.1. This license is copied below, and is also available with a FAQ at: http://scripts.sil.org/OFL

With the exception of Courier Prime, which is released under the Open Font Licence, there are no fonts "in" Scrivener. Whatever you see are fonts you've installed to the system or those that came with it.

To get Puppeteer to render emojis, you can use Noto Fonts published under SIL Open Font License (OFL) v1.1.

Fira Sans Medium: https://github.com/bBoxType/FiraSans

In terms of mono fonts that look like Comic Sans, I am surprised no one has mentioned Fantasque Sans Mono: https://github.com/belluzj/fantasque-sans

Fira is, to my eyes, an open source font which looks similar to Trebuchet MS, and there is the very popular monospace variant Fira Code: https://v-fonts.com/fonts/fira-code https://github.com/tonsky/FiraCode

Not to mention the original Fira Mono: https://github.com/bBoxType/FiraSans/blob/master/Fira_Mono_3... for a sample or https://github.com/bBoxType/FiraSans to download.

I like it a lot! Definitely in the camp of “comic sans is over-hated for poor reasons, and might even have legibility benefits for dyslexia”, and I considered a few comic sans inspired monospaced fonts before settling on Source Code Pro. The leaders were Fantasque (https://github.com/belluzj/fantasque-sans/) and Comic Code (https://tosche.net/fonts/comic-code). (Comic Code’s creator actually links to the font you linked, Comic Mono, as an example of a free font with the same spirit!)

Ultimately I found that anything descended from or inspired by comic sans ended up a little too busy for my eyes.

If paying for a font isn't your thing but you're curious this is a free version I used to use of a similar idea. https://github.com/belluzj/fantasque-sans

For Emacs I use Fantasque Sans Mono, which has a slashed zero and some other good features (e.g. clear difference between 1 and l).

I thought it would be silly or I would hate it, but the comic sans like nature of Fantasque Sans Mono really surprised me and worked well for coding/IDE use (especially in Python): https://github.com/belluzj/fantasque-sans

I know you didn't ask but I have mild dyslexia and a friend turned me on to the font he uses for coding called Fantasque Sans. I found it to be pleasantly readable like Comic Sans without being as stylistically offensive.

Fantasque Sans (https://github.com/belluzj/fantasque-sans) - I love it and use it for years in all editors! For terminal I use a patched variant of Ubuntu Mono.