Where is the best place to get images from for laser cuttings?

You could try doing a search on “Public Domain Vector Graphics” or something like that.
There is a lot of stuff out there, but much of it has copyright protection, hence the need to buy individual images, or sign up for a subscription. Even with that, you may run into restrictions based on how you want to use the image (for example personal use as opposed to making a bunch of items to sell).