Watch the 3 Ways of Playing Chords online guitar lesson by Ben Lacy from Two-Hand Groove Guitar
I have three techniques for adding chords. The first is assigning 3 right hand fingers to 3 strings to pluck chords. These are often between bass notes
Another technique is smacking the frets 12 frets above a 1-finger chord. This lets the octave harmonics ring out over your bass line. You can use it for a short stab too, depending on the feel.
The other technique is just brushing with a free finger. This works really well over a super-busy ultra-funk kind of bass part.