The Story of the H Brothers is an actual book by Sarah Wagner that helps children learn more rapidly in an amusing way. There is a very common poster also available that makes it easier for children to learn.
There are other digraphs than just listed here.
Make children make a train “chooo-chooo” sound while moving their arms back and forth like a train.
Make children say words while emphasizing the beginning CH.
Make children say “Shhh…” with their pointer finger at their lips.
Make children say words while emphasizing the beginning SH.
Make children say the TH sound, making sure they have their tongues almost sticking out.
Have children say words while emphasizing TH sound.
Have children make it look like they are whistling while making the WH sound, then make them say the WH sound while shrugging their shoulders like asking a question.