I take issue with the term "gimmick." Using familiar moves in new ways is IMO called "good choreography." If one defines using existing moves in novel ways as "gimmick," basically every use of petronella turns and waves after "Petronella" and "Rory O'Moore" is a gimmick. 

Originally had a long list of dances, but then i saw "easy" in Rich's original ask, so pared down: 

"Anthem to a Pet Ferret" by Sargon de Jesus may be of interest

"A Sure Thing" by Chris Page is challenging to teach but not actually challenging to dance

also do si do and swing the one behind offers a simple but fun twist. U can find it in Tom Hinds' "Python Reel" and Rick Mohr's "Leave the Wine"