Easy loop

The Non-Slip Mono Loop is also known as the “Kreh Loop” as it has been popularized by fishing legend Lefty Kreh. As its name suggests it forms a non-slip loop at the end of a fishing line. The loop connection to a fly or a lure can give the fly or lure more natural action. Some fishermen find the Kreh Loop easier to tie than the similar Rapala Knot and equally reliable.

https://www.netknots.com/fishing_knots/non-slip-loop-knot