The Avestan alphabet contains fourteen vowels and thirty-seven consonants (including orthographic notes and whatnot,) used for commentaries on the Avesta in Middle Persian (also known as the Pazand script.) Based off the transliteration guidelines published in Lesson One - Introduction to the Avestan Alphabet, a keyboard, featuring all of the Avestan alphabet has been readily created by Xavier Misri for academic and recreational use.
The Avestan keyboard was designed in mind to ensure that the typing of Avestan script was both accurate and efficiently done. Designed using the Ukelele Keyboard Layout Editor, the Avestan keyboard provides full Unicode support and is designed to properly meet academic standards. Features include:
Native macOS keyboard layout compatible with Apple’s system input framework System-wide usability across all macOS applications that accept text input
Logical use of modifier layers (Shift, Option, Option-Shift, etc) to maximize character access without excessive disorganization.
Consistent and predictable character mapping to support rapid memorization, according to the aforementioned transcription guide.
Note: Blank keys (like the ones seen in the image below) are left blank on purpose, since the Avestan keyboard was really designed for transcription purposes, and as such will not work.
Sample image of the Avestan keyboard.