Comet solid balsa kits - 1/72, 1 block and 2 sheets balsa + instructions - add razor blade and sand paper and you had "Home Amputation in One Easy Lesson".
Berkely ducted fan kits - Neat looking kits and instructions, unfortunatly you needed a degree in engineering to get them together - had 2, a T-33 and an F4D. .049 powered
Starfix - Wife bought 3 (Mustang, Spitfire and Messerschmidt) for 10 cents each (unopened) at a yard sale. Opened and figured out why - went directly into file 13.
If you want strictly plastics:
Starfix - note above
Lindbergh - 95% were dogs in outline and fit
Aurora - Even clunkier than Matchbox - raised areas to indicate where decals went - molded in weird colors (bright yellow Zero, metallic red Bf109, black Fw190, metallic green Albatross)
Having said all that, I've built my fair share of Linbergh and Aurora kits.