Toddlers have very short attention spans and keeping a group of them all paying attention at the same time is tricky. You and your activities have to be engaging and entertaining. If so, parents can sit behind a small child and help them to clap. Lots of hands-on. I collect anything musical from anywhere I can find it, right down to pots and pans.
Dollar stores have great items too.
Of course you need to watch for parts that come off. Obviously the youngest of these children won't be able to learn the words but giving them a chance to enjoy your singing and move with it is the greatest gift to them. Also, you could provide words to parents for the simple rhymes. In the process I am able to teach the student how to play and handle many types of rhythm and Orff-style instruments, to develop their singing voice, to improvise on instruments, and other musical skills. If the teacher requesting help would like to contact me for more detailed information I would like to help in any way that I can.