Blue Saree: Blue is a lively and lovely color, you must choose a bright blouse that is yellow, Light green, Silver, White or Nude shades.
As blue itself is very Attractive , you can keep the contrast blouse suble , yet classy.
Green Saree: Green comes in many shades. So , when you are picking a contrast blouse . you must check what shade of green your saree is. If it is a lighter Shade, you can opt for pink, white, or silver colored blouses.
If it is in darker shades , then you can go for dark colors like purple, blue black, red or maroon