I remember flying successful loops with a Barnaby back in my childhood; sadly, it looks like his book (How To Make and Fly Paper Airplanes, Ralph S. Barnaby) may be out of print.

I'm sure there are many newer books and designs these days, but that was the one I knew and loved.

Maybe the Phat Glider or Boomberang I from John Collins https://www.youtube.com/watch?v=5pKicjvC6Uo

Probably the Spin Plane. I've built similar to this and it loops a bunch.

The balsa wood one with a rubber band and plastic propeller. ;)