There are several variations of this around. Unfortunately, the most reliable source of a keyboard in this format is a shareware, not a freeware, product. Like keyboards, fonts are tied to encodings. Fonts that work with ASC will not work with KOI8. If you are supporting multiple encodings, this can become very confusing.
Fonts come from a variety of sources and are of widely varying quality and ease of installation.
If you have OS9 and add Cyrillic support, you will get a basic set of ASC fonts. For additional fonts, or for ASC or KOI8 fonts, you'll have to make some additional installations. We will point to towards some additional free fonts when you're further along in the process. There are also a fair number of commercial and shareware fonts. One problem you may run into is that fonts work with specific script ranges .