This activity does not require much stuff and precision. It will give your toddler a chance to see colors interacting and a chance to know his or her creativity and inclinations. Just hand them an art sheet and some paints. You can join in, but please do not guide or correct them too much during the activity, let them work with their own creative perception.
Designing a collage can really help them identify shapes and connections. Mind you, it could be a messy idea but it is a guarantee that your toddler will enjoy it. Start off with selecting easy shapes to form a flag or any other simple shape. Gradually you can move on to toys, etc.
This activity improves the mental focus of the toddler and is also a great bonding activity. You need to be careful as the kid will be playing with glue. In fact, this could be a great way for you, to get back to your creative side. Make the outline of the drawing yourself and teach the toddler how to fill it up.
Greeting card is the best way to reach out to dear ones on special occasions and a great gesture as a personal greeting from heart. So, instead of buying cards, get your happy helper to make them. Be it Easter, Christmas, Halloween, Valentine's day or the Chilly festival, start making cards with your kid and help him with colors and designs for the occasion.
Wall decoration is a bold idea best left to the discretion of parents. You could paint the toddlers room (or the entire house, if you like) with chalkboard paint making the house your kid's canvas. There are many decorating ideas, that may help the toddler and you. After chalkboard painting, you just need a stock of chalks for your toddler to craft away.
There are many more ideas like pottery, pot painting and creative writing, that could really help the toddler. Nonetheless, those require expert guidance and a certain level of motor skills and developed creative thinking ability.
So, wait a little and take up craft ideas discussed here and then go for the advanced ones. Further, nothing can work without requisite attention from the parents. So, try to make sure that you are around, when your toddler is doing these activities.