One pattern, different yarns
One great thing about crocheting toys is that the exact size is rarely important, which gives you the opportunity to experiment with all kinds of different yarns - use bulkier yarn (or crochet holding multiple strands of yarn together) and you'll get a larger toy, use finer yarn and you'll get a smaller toy, pick eyelash yarn for a fuzzy look, cotton or viscose for a nice smooth surface, alpaca or wool for a more natural and rustic feel. With just one pattern you can create so many different looks.
If you pick a yarn that is significantly lighter or heavier (i.e. finer or thicker) than the one listed in the pattern, you'll also need to adjust the size of the crochet hook and eyes, noses, joints or any other details you want to use, more about it below.