This is an excellent knot for various uses, very strong knot. It's used in mountain climbing. The figure 8 family of knots only lower rope strength by approx...
Double Figure 8 (2 loops)
How to tie the Double Figure 8 on a bight knot.
How To Tie A Double Figure 8 Knot
Double Figure-8 Fisherman's Knot
Double Figure Eights with Banyan