Back, berk, Brok, beak, beck, book, break, brook,
wake
Some words containing k, g, w:knowingtweakingwakingwalkingwhackingwinking
invoke
Bookkeeper and jackknife are words. They contain the letters kk.
None, there is no such letters in the English language.
Kebobs (as in shish kebobs).
These letters could be rearranged to spell the word 'banker'.
bo, no, on
poke
Buckle, Bucket, Ruckus, Sucker, Bucked, Flukes...
big gab bag wag wig
freak stab