Not sure what you are asking exactly, but if you are looking for a chord that will work underneath this riff, try:
G, G6, Gm, Gm6,
or
C, C6, CMaj7,
or
Am7, Am7(9)
or
F7, F9, FmMaj7,
If you are looking for a chord to play after this riff, try any of the above, or try:
D7
or
G7
or
E7
or
C7
Hope this helps