There is this variation of the dragon curve:
order: 10
axiom: FX
angle: 90
X -> X+FYF-
Y -> +FXF-Y
This avoids the self-intersections (like a similar depiction of the Hilbert and Gosper curves), yet it remains relatively simple, and reveals more of the structure inside the bulk of the curve.It's especially pretty when completed into a twin-dragon with the axiom: FX+F+FX+F+ and same rules as above.