Education.com is a wonderful site with tons of worksheets organized by subject and grade level. They have plenty of consonant blend and diphthong worksheets to help the kids learn. (You do have to join, but it’s a free membership.)
Kids Learning Station has a nice set of consonant blend worksheets, including standard fill-in-the-blank, word searches and matching. These are fun, colorful worksheets!
Lots of colorful vowel and consonant blends and digraph worksheets to be found at this website. There is also a helpful alphabet and phonics test to make you aware of which phonics sounds your student does not yet know.
Free Phonics Worksheets has a big selection of worksheets for consonant and vowel blends. There are a variety of activities including crossword puzzles, color-by-number, fill-in-the-blank, matching, etc.