Below are all codepoints supported by Athena Ruby, with standard Unicode in the first half and nonstandard in the bottom.
Standard Unicode points
All characters
, . / : A B C D E F G H I J K L M N O P Q R S T U V W X Y Z [ ] a b c d e f g h i j k l m n o p q r s t u v w x y z | · ˁ ˊ ˋ ˙ ̀ ́ ̄ ̅ ̆ ̈ ̓ ̔ ̣ ̷ ͂ ʹ ͵ · Α Β Γ Δ Ε Ζ Η Θ Ι Κ Λ Μ Ν Ξ Ο Π Ρ Σ Τ Υ Φ Χ Ψ Ω Ϊ Ϋ α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ ς σ τ υ φ χ ψ ω ϊ ϋ ϗ Ϙ ϙ Ϛ ϛ Ϡ ϡ ἀ ἁ ἂ ἃ ἄ ἅ ἆ ἇ Ἀ Ἁ Ἂ Ἃ Ἄ Ἅ Ἆ Ἇ ἐ ἑ ἒ ἓ ἔ ἕ Ἐ Ἑ Ἒ Ἓ Ἔ Ἕ ἠ ἡ ἢ ἣ ἤ ἥ ἦ ἧ Ἠ Ἡ Ἢ Ἣ Ἤ Ἥ Ἦ Ἧ ἰ ἱ ἲ ἳ ἴ ἵ ἶ ἷ Ἰ Ἱ Ἲ Ἳ Ἴ Ἵ Ἶ Ἷ ὀ ὁ ὂ ὃ ὄ ὅ Ὀ Ὁ Ὂ Ὃ Ὄ Ὅ ὐ ὑ ὒ ὓ ὔ ὕ ὖ ὗ Ὑ Ὓ Ὕ Ὗ ὠ ὡ ὢ ὣ ὤ ὥ ὦ ὧ Ὠ Ὡ Ὢ Ὣ Ὤ Ὥ Ὦ Ὧ ὰ ά ὲ έ ὴ ή ὶ ί ὸ ό ὺ ύ ὼ ώ ᾰ ᾱ ᾶ Ᾰ Ᾱ Ὰ Ά ᾽ ῀ ῆ Ὲ Έ Ὴ Ή ῍ ῎ ῏ ῐ ῑ ῒ ΐ ῖ ῗ Ῐ Ῑ Ὶ Ί ῝ ῞ ῟ ῠ ῡ ῢ ΰ ῤ ῥ ῦ ῧ Ῠ Ῡ Ὺ Ύ Ῥ ῭ ΅ ` ῶ Ὸ Ό Ὼ Ώ ´ ῾ ↀ ◌ ☧ ⸉ ⸊ ⸣ 𐆂 𐆄
Experiments in advanced features
Ligature test: ΑΒ ΓΩ ΑΒ ΛΙ
Variant-one: ABCDEFGHIJKLMNOPQRSTUVWXYZ ΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΩ
Variant-two: ABCDEFGHIJKLMNOPQRSTUVWXYZ ΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΩ
Variant-three: ABCDEFGHIJKLMNOPQRSTUVWXYZ ΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΩ
Variant-four: ABCDEFGHIJKLMNOPQRSTUVWXYZ ΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥΦΧΨΩ
Variant ligature test: ΗΡ ΗΡ ΗΡ
Contextual alternate test: A̅ B̅ C̅D̅
Variant contextual alternate test: pending
Private Use Area
Not the optimal method for accessing the character variant you're looking for, but it's there if you need it.
All characters
Experiments in advanced features
Stacking decoration: