there are a few that I've looked at. Avery 5395 - 2.33"X3.38", 5453 - 3"X4", 5978- 4"X2", 6462-3.33X4..
Just take a piece of paper and wrap it around your bottle draw out a little square the size you want it then measure it. find an avery label that the closes to the size you want to use.
I know it's not a lot of help but it's a start.