I use a few websites, clipart library is the one I use most. There are so many bloggers that send you free printables if you sign up to their newsletter. But there are many websites that offer free ones but not all are free for commercial use so check first.
Just google it, there are a ton of free printables online. Stencils are not normally free.
I google the type printable or stencil I want and then have tons of ideas
Lynneclare you can go to Pinterest.com and search the kind of printables you are interested in. There are many to choose from on different websites.
I have a FREE Resource Library with free printables, graphics, images and SVG files.