iReal Pro supports a wide range of chord qualities. The screenshots below show every quality available in the latest version, taken from the chord picker in the Editor, where you can always browse the full list.

The chords above use a few compact symbols. Here is what they mean, with the shorthands and alternate spellings iReal Pro also understands:

- = minor (also type m or min)
-^ = minor-major 7 (-^7)
^ or ∆ = major 7 (also type maj7)
^9 = major 9 (also type maj9)
^13 = major 13 (also type maj13)
^+ or ^#5 = ^7#5
^b5 = ^7b5
^#11 = ^7#11
o = diminished (also type dim)
o7 = diminished 7 (also type dim7)
ø = half-diminished, min7b5 (also type m7b5)
+ = augmented (also type aug)
7+ = 7#5 (also type 7b13)
9+ = 9#5
add9 = add2
-add9 = -add2
2 = sus2
sus = sus4
7b9sus = 7susb9
7b13sus = 7susb9b13
alt = 7alt

Examples:
C-6 (C minor 6)
C-^ (C minor-major 7)
C^#11 (C major 7 #11)
F/C (F with C in the bass, an inversion)
C-add2 (C minor, added 9th)
C^+ (C major 7 #5)