This is a simple pattern for a baby dragon.
Gauge does not matter for this pattern. It will vary depending which yarn and hook you choose to use.
For the one I made, I used around 100 yards worsted weight yarn, a small amount of fluffy yarn, and a size G crochet hook. The dragon is about 12 inches long.
Besides the yarn, you will also need stuffing material, safety eyes (unless you embroider the eyes), yarn needle, and a stitch marker.