1996 trans fluid

i changed filter. and added vavolene mercon v full synthetic. didnt have enough and local gas stations dont have it.. so my question is what type should i have used and can i mix anything with this?

Is there a reason you can't go back to where you bought the fluid and buy more? You should only use Mercon V when adding to what you have. If you can't find Valvoline then another brand would do in a pinch as long as it is Mercon V.