This block of chords is a standard set of basic guitar chords. Some fingering options are on each side of the chord. Chords with only one fingering are the best fingering option.
When we see a chord symbol [which is also a scale symbol], it is up to us how we voice it. We can even change the voicing of the same chord within its time frame (use 2 or 3 types of Em for a measure). We can also have changing elements (parts of the chord are changing - being melodic within harmony).
This is an alphabetical Dominant chord scale for the natural tone roots. These are all Major chords with a flat 7. Dominant chords are built - Root-Third-Fifth-Flat 7 [R-3-5-b7].
Dominant chords are typically only the V chords in a Major key, yet in Major Blues, we can use all dominants.
Learn how those were created with EON. Once we know chords in a key, and what key a song is in, we can start to predict what might be used in a song.