Students often ask what other chords can be used in a song instead of straight majors and minors, just to liven things up a bit. There are lot of ways to do this by adding different notes from the scale and let the ear tell if the embellished chord clashes with the melody line.
Example 1 shows the harmonized major scale in the key of C. In songwriting its not possible to use a different chord for each melodic note. There are three primary chords formed on root, sub dominant and dominant position of the scale that supports each melody note in that particular key. Example 2 is in the key of C and the chords formed on root, sub dominant and dominant positions are C, F and G. so to begin with this is a good place to start - to harmonize the song in three chords. Example 3 shows how by adding different scale tones to the basic triad new chords can be constructed. Example 4 shows how adding scale tones to minor triads can add that essential dash of color. Even dominant chords has alternatives (Example 5). All added notes are from the scale so nothing will sound bad. use your ears to decide. Keep experimenting.