Watch the iii IV I online guitar lesson by Brad Carlton from Guitar Lab: Diatonic Chord Progressions

This lesson presents the iii IV I progression in the six keys: E, G, A, B, C and D. In the key of E the chords are: G#m add#5, A add9, E; Key of G: Bm add4, CMaj7, G6; Key of A: C#m7, D 6/9, A add9; Key of B: D#m add b6 add b9, E, B add4; Key of C: Em, FMaj7#11, CMaj7; and the key of D: F#m 7/11, G6, D 6/9. For each iii IV I progression, the modes are: phrygian, lydian and ionian. Each mode reveals the available extensions and melodic tones that are available for rhythm and soloing. Use the following list of formulas to understand your options:

Ionian 1 2 3 4 5 6 7
Dorian 1 2 b3 4 5 6 b7
Phrygian 1 b2 b3 4 5 b6 b7
Lydian 1 2 3 #4 5 6 7
Mixolydian 1 2 3 4 5 6 b7
Aeolian 1 2 b3 4 5 b6 b7