Songs in which you can adjust the volume on a particular guitar track within the song, allowing you to play in place of that guitar track, while still playing with the rest of the song. This is extremely helpful for applying what you've learned to practical examples.
Chord charts
Chord charts or diagrams illustrate how to shape (create) various chords. They will indicate which strings and frets (and sometimes which fingers) to use to create the chord.
Modes
A mode is a group of intervals and the degrees that correspond harmonically with the chord being played underneath. Modes might have a parent scale attached to them, but they are not scales. Modes can change throughout the song, but still use the same scale and be in the same key. Scales, in contrast, cannot change without changing key.
Ear training
Ear training is a process in learning to identify intervals, chords, rhythms, and other basic elements of music.
Reading tablature
Tablature(or Tabulature) is a form of musical notation, which tells players where to place their fingers - which string and which fret - on the guitar rather than which pitches to play.
Genre styles
This refers to various genres or styles within a particular genre. Some genres include rock, blues, jazz, R&B, funk, latin, classical, etc.