I have started to create some flash cards using a space repetition flash card program called Anki. These flash cards can be used to supplement the physical materials (which haven't been released yet). You can create an account on Ankiweb and use it on your computer for free. You can also download Ankidroid on your Android phone for free or AnkiMobile on your IPhone for $25.
Ear Training Deck 1 This deck can be used to supplement the Tetrachord Cards (not released yet). The goal with this first ear training deck is to recognize what type of tetrachord you are hearing---diatonic, soft chromatic, hard chromatic or enharmonic. Most cards pair tetrachords from two different scales together to help students learn to differentiate between them. This deck does not teach the theory that helps with audio recognition. If you need to learn about this theory then I recommend watching Basic Byzantine Chant Theory Lesson #1. As you begin recognizing the tetrachords correctly then you should begin trying to produce the pitches yourself. There will be a second ear training deck soon that will focus on helping you practice chanting the pitches correctly.
Nick Jones from byzantinechant.org collaborated with me on this deck and recorded the audio for each card.
The ear training decks make use of the graphics from the Tetrachord Cards because the graphics will aid in memorization. Instead of seeing an answer written as "the lower tetrachord of the hard chromatic scale" students see a visual represention which includes the martyrie and intervals associated with this particular tetrachord.
Deck #1: Once you have mastered these cards then you will know which martyrie symeion (the bottom symbol in the martyrie) are associated with the diatonic, hard chromatic and soft chromatic scales. This helps beginners know which scale they should be chanting in when they look at a new piece of music.
Deck #2: As you are mastering basic music (like that in the Level 2 Repertoire) then you should begin studying this deck so that you can identify which Greek letters go with which martyrie symeion to make up each martyrie in the three basic scales. This knowledge is one of the necessary skills that will aid you in sight reading music with fthore (symbols within the music that indicate a change to a different scale's tetrachord).
Deck # 3: This deck prompts you with a scale and pitch and asks you to come up with the martyrie on your own. This is similar to Deck #2 but coming up with the martyrie completely on your own is more difficult than simple recognition. When you master this deck then you know the martyrie for these three scales really well.
Later Martyrie Decks: At some point I will create decks for Grave Diatonic and Grave Enharmonic from Zo.