A more emphatic five

The [five] chord plays such a dominant role in music that it's called the dominant chord. And one of the common uses of alternate bass notes is to build up the dominant chord, to make it more emphatic, and to heighten the sense of expectation that it carries.

Of course, the simplest way to make a [five] chord more emphatic is to add the seventh, making it a [five]⁷. This chord type, a major chord with a minor seventh, is called dominant seventh.

Here are some other chords and sequences of chords that are commonly used to take the place of the dominant chord:

[one]/[five] [five]
In C major: C/G G

[four]/[five]
F/G

[two]m⁷/[five]
Dm⁷/G

[five]sus⁴ [five]
Gsus⁴ G

[five] [five]sus⁴ [five] [four]/[five]
G Gsus⁴ G F/G

[five]⁷sus⁴
G⁷sus⁴

[five] [five]⁷sus⁴
G G⁷sus⁴

[five] [one]/[five] [five]⁷
G C/G G⁷

You can invent other possibilities. The key to all of these is that the bass stays insistently on the dominant (5) note until a cadence is finally concluded with a move to [one]... or sometimes to [six]m.