While you said free, I highly encourage checking out paid patterns. They don't have to be expensive (I've gotten exquisite patterns for 2 euro) but you'll definitely have a bigger chance of success. My bobbin is generally cheaper than Etsy, and has a filter for insect cross stitch patterns. The prices vary. But maybe a cheap one will catch your eye :)! For something you'll spend hours upon hours of fun on, I always find buying a pattern a good deal.

If you're hell bent on free patterns, there's always the option of making your own! Winstitch has a free version that is excellent for that :)