Libre font databases with fine-grained faceted search

Question

I'm having difficulty finding suitable libre typefaces. Some sites, like Google Fonts, provide a small amount of faceted searching (or search filtering, if you prefer), but I haven't found any sites where these facets are adequately comprehensive/fine-grained.

When trying to identify suitable typefaces in these databases, the user is therefore still faced with laboriously wading through huge lists of typefaces and cataloguing them themselves - largely by eye - which is obviously inefficient. It's hard to believe that the design community as a whole finds this acceptable, so I'm really hoping that other, better databases exist and I just haven't found them yet!

So, are there any typeface databases that allow faceted searching by all or most of the following characteristics?

• Vox-ATypI classification
• Whether I, l and 1 are identifiable without reference to each other
• Whether rn and m are easily distinguishable from each other
• Whether a and o are easily distinguishable from each other
• Whether g is double or single-storey
• Whether lining numerals are included
• Whether typeface is monospaced
• Whether available under an FSF-approved font license

Answer 1

Would you want to search for fonts where the rn & m are not easily distinguishable?

These metrics/facets are not defined in a font file or available in meta data. And can be Subjective. Making it difficult to create clear search facets.

Text or bitmap search can auto categorise and make safe assumptions about their content. There is a lot of value and use cases for computer vision and full text search. A font search would be a manual process of assigning these properties.

It is a good idea for anyone that wants to spend the time. But with the thousands of fonts out there each time you wanted to add a new metric, you'd have to manually spend hours defining this. Or with adequate funding create machine learning software for vector that can recognise monospace/serif/sans-serif/script or g is double or single-storey

An alternative idea is to rasterise the font and then take advantage of Computer Vision technology. Similar to Font Squirrel image font search. But this wont have the facets you desire. This could be a good foundation for software that can identify such things.