You can use the plugin.json file.
In nodebb-theme-lavender for example, plugin.json has:
"staticDirs": {
"vendor": "static/vendor"
},
there is a file called masonry.js that can accessed at http://yourdomain.com/plugins/nodebb-theme-lavender/vendor/masonry.js
So in your case, you can use in your plugin.json
"staticDirs": {
"fonts": "static/fonts"
},
and access it at http://yourdomain.com/plugins/nodebb-theme-yourtheme/fonts/thefont.ttf
you can do multiple routes with staticDirs like:
"staticDirs": {
"fonts": "static/fonts",
"scripts": "static/js"
},
or make the whole directory reachable like:
"staticDirs": {
"static": "static"
},
The later is what I usually do.