A strong grip has always been important to me.
over the years I've done all forms of grip work, at the end of the day nothing conditions the arms like loaded carries, even BB curls are great.
Early on I tagged weighted ab crunches (one set) to the end of a workout, not so much now.
doing these properly, certainly thickens the waist (torso).
One exercises I like to do and do often are side bends, they also strengthen muscles around the spine, which is what I'm after.
Calves?
when I look back at photos of myself before I started working out, I looked like a stick insect, I worked on my calves at times, I think it all helps, but the time spent compared to other exercises over 30 years was miniscual.