We all have habits and when we are busy that is when these habits are most useful but sometimes we need to shake it up a little. You don't need more toys you just need to use them differently. Take a moment and try something you don't normally do:
1. If you always have the plastic animals on the floor put them on a table instead.
2. Just put out all the cows this time which can lead to - mother, father, baby discussions and what does this animal eat; where do they live; what do they say; a song about this one animal: "I went to visit a farm one day, I saw a cow across the way and what do you think I heard it say? Moo, Moo, Moo."
3. Place plastic animals hidden in the garden.
4. Create a little environment for the animals - I use green felt, leaves, rocks and large pieces of bark. You could create a sea scene by actually putting sea creatures in shallow water.
5. Put the plastic animals in the playdough, or in the sandpit, or in the doll's house.
6. Leave them in the box with the lid off and see if any children go to this toy.
7. For 1 year olds have 2 containers so they can play moving the plastic toy from box to box.
Of course while I have made these suggestions with plastic toys, they could be used for many other play things. Have fun and be creative.