Not free, but these are darling and reasonably priced:

http://www.designsbysick.com/details/watercans

also

http://www.ericas.com/freedesigns/jnowicki01.htm
http://www.embroidery.dk/cn.asp?CID=846

scroll down on this page:

http://www.emblibrary.com/el/searchresults.aspx?search=watering%20can

there maybe some on annthegran website.
You will need to register.

got a good answer so here is flowers for all

Here are some watering cans for you, and if you can wait until Tuesday-Wednesday or Friday, there will be sales.