When I was going up on rooftops for HVAC if I needed a ratchet I used a 3/8" Armstrong. Low tooth count. It seemed to do the trick for anything I might need, as nothing was heavily torqued and if something was rusty I used a breaker bar.
Now that I am retired, and no longer work on motorcycles and cars (if I can help it) it's mostly appliances and bicycles. But, I have drawers full of ratchets I have picked so I have tried most things by now.
1/4" - I usually use nutdrivers, honestly. If I needed to grab a ratchet, it could be anything handy; Armstrong, Proto, Herbrand.
3/8" - Cornwell stubby. So handy for what I am doing.
1/2" - Snap-on stubby, or on rare occasions a Cornwell long handle.
One thing I have found is that I dislike round head ratches, and have never used a flex-head. And I have never noticed a need for a high tooth count.