B minor: i - bVI (B minor - G maj7(#11))

Suggested Scales: B minor, G lydian

C major: I - IV - vi - IV - V (C - Fmaj7 - Am - Fmaj7 - G)
Suggested Scales: C major, C major pentatonic

E major: I - V - vi - IV (E - B - C#m - A)
This is one of the most common progressions in popular music. In the key of E, try to take advantage of the open E (1st) and B (2nd) strings.
Suggested Scales: E major scale, E major pentatonic (same notes as C# minor pentatonic)

12-Bar Blues in E: I7 - IV7 - V7
A very common pattern and a very common key for blues on guitar. Try putting in a quick resolving phrase over the blank spot in the 10th bar.
Suggested Scales: E minor pentatonic/blues, E mixolydian, E7 A7,B7 arpeggios

12-Bar Blues in A: I7 - IV7 - V7

Suggested Scales: A minor pentatonic/blues, A mixolydian, A7 D7 E7 arpeggios