If you, too, would like to turn your smartphone into a microscope, here is a very cheap way to do it: https://www.instructables.com/id/10-Smartphone-to-digital-microscope-conversion/
If you do this, just make sure that your lens is secure if you leave the house. My husband tried this method and it worked great… until he lost the lens while out on a walk.
If you decide to collect pond water, the water along the edges of the pond will have the most creatures. Just be sure to wash your hands well afterwards!