I'd put on there any Inline/V8 or V12 you have to crank over yourself.
That thing Jeremy Clarkson drove that had no valve covers or hood so you got hot oil on your face.
A 1930 era snowplow with no power steering, huge steering wheel, crashbox trans, and block & tackle plow lift.
A motorized bicycle built by oneself operated in city traffic.
A t-bucket kit bought from someone else's failed project with no instructions and 95% of the parts. Rolling with one of the least impressive smog era 100 hp 302ish inch V8s, with the vacuum hoses plugged with pencils and golf tees and a fufu air cleaner from pep boys.
so basically anything where you have to turn a wrench, have huge upper body strength, or stones down below.