Five Great Websites For Speech-Language Therapy Materials
communication --> speech --> phonology --> phonology workshop --> stopping
...you will come to a page where you can select from many different minimal pairs for the phonological process of stopping. Or, you could opt to select only the fricatives, etc. From there, use the toolbox on the right of the screen to generate worksheets, picture cards, game boards, and more!
Therasimplicity also has a massive index of ready made materials that you can browse through.