First: try searching for "bongs." (At the time of writing we notice that the bong selection contained mostly hand pipes.) The bong selection was also not very high, but we were pleased to see some hand made water pipes in the mix.
Second: you can try searching for water pipes, but we found the results to be poor as well, and almost yielded the exact same listings as the first result (although we noticed more bubblers this time.)
Unfortunately, it we could not get very many results to show up when trying to find ETSY bongs, but hey! If you want to buy bongs with fast 1-week shipping (for the USA), you can always check out the collection at Rockygreenking.com.