In real life, my rating is about 1500. I play the Icelandic (within the Scandinavian) whenever I get the chance. Also the Budapest. I have had great success with the Icelandic, including in OTB play against opponents 100-200 points higher than me. Not so with the Budapest though.
It would be interesting to see a list of gambits and the corresponding rating at which they stop being effective.
Icelandic is strong. I like the white side of the Panov and was forced by bad losses in Icelandic to dig in and learn it well even though it is rare.
He forgot the Lastrank gambit, 1. e4 e6 2. d4 d5 3. exd5 c5, which should probably be the last ranked gambit on the list.