I get requests for infant and toddler activities all the time. One thing we love to do at our house are discovery bins. I usually stick to colors as the main theme as my daughter is still young ( 14 months) as she ages I will do shapes and letters too.
The two biggest pieces of advice I have for parents wanting to do these are :
1. Keep them simple - 5-6 things MAX. Fewer are usually better.
2. Choose a variety of textures.
Young toddlers and infants are still exploring most things through touch ( often with their mouths so be prepared with safe objects) so to have a variety of textures will make the bin more interesting.
Clear the area of other distractions and narrate their actions . For example ; " You have a bumpy red saw." " That's a crinkly red ring." etc...