Free play is important at that age. DD went to an in-home daycare that specialized in 0-18 months. They didn't do a lot of crafts at that age. But they did a lot of active playtime. They went for stroller rides. They took one good nap.
There should be a safe place for free-play set up so that they can play independently and learn and explore. Have enough unique push toys, riding toys, etc that the kids each have one to play with.
If I remember any other activities they did, I'll let you know. If I speak to them, I'll see if they have any good online resources.

One thing my daughter loved at 12 -18 months was shaving cream. They put smocks on the kids & shaving cream on the table & let them play away! Large beads & strings are good - develop sorting & hand eye coordination - that's a free play type activity, though. The children were taken for a walk outside every day, weather permitting.

Senosry activities are great at this age. Fill a small blow-up pool with water and dishwashing liquid and give each kid a straw & let them blow bubbles. The next week, fill it with small plastic balls and let the roll around in it. The next week, feel it with shredded, crumpled up paper and let them squirm in it. The next week, fill it with dry beans and rice and give them lots of cups to pour it with. The preschool where my older 2 kids went specialized in sensory play and they were so creative. They didn't do structured crafts, but everything was approached from a sensory perspecitve. Try to think that way for this age group and they will love it.

Other things I remember from that school - when they are outside, give them big paintbrushes and buckets of water and let them "paint" the building. Give them buckets of soapy water and sponges and let them "wash" the windows. And, of course, PLAY DOUGH and rolling pins and cookie cutters is the #1 hit with that age.

big bubble wrap--let them jump on big bubble wrap.

I just wanted to thank all of you who replied.There are some good ideas here.Thanks for sharing.

COOL! Bubblewrap!!!!:)
I was going to chime in with Mommabear about the sensory activities. Feeling, touching and exploring are so very important at this stage!! Finger paints, felt, velcro, chalk, all sorts of things that can be done outside too! WATER!!:) Assumming that there are plenty of adults around to supervise! Help them explore their senses!:) No, don't have any sites, just words from me!:) Great luck!!

I worked in daycare while I was in college. All of the above activities are great. One thing I would mention though, I don't like the shaving cream. I would suggest edible things that are similar such as pudding, Redi Whip, ect. Children of this age put everything in their mouth naturely. I like to keep it to things that are safe to go in the mouth, but that is just me. We did the Redi Whip at the center I worked at. We put the kids in high chairs and let them play in the cream.

Other ideas are bubbles. You can use the automatic bubble makers if you like so you don't have to blow them repeatedly. The kids love it.