THEME: phrases starting with FOR but which could be read without FOR [most clever]
GOOD ONES: King's downfall MATE [in chess; also at times in royalty]
Balancing aid EAR [I was sure it was BAR]
Coat material PAINT
Boat propeller OAR [oldie but goodie]
BTW: Excuse
that last jeer? FORGIVE A HOOT [lack of parallelism: the word "that" is definite, but "a" is indefinite]
Discovered accidentally
LIT ON [Maybe found in some on-line glossary, but it's not in English… "hit upon" is the term.]
RATING:
Three grins = Loved it; Two grins = Enjoyed it; One grin = A bit bland for my taste; One teardrop = Not much fun