Virgin Atlantic (UK)
Premium Economy: free amenity kits on overnight flights, newspaper, and drink
Economy: drinks and snacks goodie bag for kids (non-UK flights only)
Air Malta (Malta)
head rubs & hand massages
Turkish Airlines (Turkey)
free city tour "Touristanbul" on layovers 6 hours or more
Scandinavian Airlines (Sweden)
Exercises you can do in the Chair
Business Class: Handle Bar to help stretch and relax aching back muscles
Air France (France)
La Premiere / First Class: three course Michelin gourmet meals
Premium Economy: glass of champagne with savory appetizer (select routes)
KLM (Netherlands)
World Business Class: comfort kit by Viktor & Rolf
Delft Blue porcelain miniature of a Dutch house filled with Genève (I never got this, maybe it's new?)