A call and response song I like to use to differentiate between the childrens’ voices and my own. They respond back to me up an octave.
Key of G, normally on guitar.

Down by the Bay (Down by the Bay)
Where the watermelons grow (where the watermelons grow)
Back to my home (Back to my home)
I dare not go (I dare not go)
For if I do (For if I do)
My Mother will say (My Mother will say)
Did you ever see: *Insert rhyme*
Down by the Bay!

-a fly wearing a tie
-a goose kissing a moose
-a llama wearing their pajamas
-a dog sitting on a log
-a cat wearing a hat
-a bear combing his hair
etc. I like to have the kids come up with their own rhymes or I will use their names to rhyme one.