Start here. These charts all can be played with G, C, D, and Em (in any order and iteration). Utilizing a capo, we can not only play songs in the key of G, but in Ab, A, Bb, B, C, and Db while still using G chords. For practice with A chords/numbers, the charts in the keys A, Bb, B, C, and Db can be used. 

These charts all can be played with G, Am, C, D, and Em (in any order and iteration). The same keys appear as the 4 chord charts above (G, Ab, A, Bb, B, C, and Db)

These charts are advanced and should be attempted only after you've played many 4 and 5 chord charts from the above links. 

These charts utilize not only 1, 2m, 3m, 4, 5, and 6m chords, but non-diatonic chords like 2, 3, 4m, 5m, b3, b6, b7, etc. 

The same keys appear as the 4 and 5 chord charts above (G, Ab, A, Bb, B, C, and Db).