Options abound.. here are 4 i've got here.

German Magura HS33 hydraulic Rim brakes work extremely well.. Smooth ..

another fine, cable operated, cantilever Rim Brake, no longer made,
Scott- Peterson, the Self Energizing mech, has a helical cam and coil spring,
in each cantilever caliper.. and is pulled tighter by the rotation of the rim ..
and so the brake lever has some mechanical assistance..

I have them on 2 different touring rigs here..

in really foul weather the disc brakes on my recent bike friday work well,

and my Drum brake hub equipped bike as well, I use it's smooth modulation to good effect
on a bike I leave ,now, equipped with studded tires for Icy road days.