....well I'm getting close but there are still quite a few to try!

Tried and liked

Classical, folk, "celtic", blue, rock and jazz guitar
Bass guitar
Mandolin
Octave mandolin
Tenor banjo
5-string banjo
Bouzouki
Portuguese guitar
Mountain dulcimer

Tried and player found "skill-challenged"

Melodeon
English and Anglo concertinas
Saxophone
Keyboards

Currently under trial and "promising"!

Irish D flute

On future "wishlist"

Decent resonator guitar

The Good Lady says I am "best" (in the broadest sense of the term) on mandolin but I think perhaps guitar...

Peace

moo