I've made rounded ones myself. Take a saucer or soda can top or something round (a compass works too!) and make an arc, then measure how long you want the blade to be, and draw another line.
A tip that one of my grandmothers friends taught me, for easier applique, use some double sided fusible webbing like heat n bond lite. Trace a tiny bit of the arc or point and fuse to the blade. Then you can machine or hand applique it down.