The -aught words

I've been thinking about the words which rhyme with "caught".
I noticed that, with very few exceptions, they all derive from words which do not rhyme. Bizarre. But that's English. Gotta love it.

word	derived from
ought	owe
brought	bring
caught	catch
fought	fight
taught	teach
thought	think
fraught	freight
onslaught slaughter	slay
distraught	distract
draught	draw (though it's generally pronounced "draft")
sought	seek
wrought	wreak
claught	cleek
bought	buy
haughty	high
flaught	fly