I don't run pockets on the belt. Most do I reckon. But, I just never saw the need in doing so. Every pack bag I run has a pocket or zippered compartment for GPS and headlamp. So, before I bought any, I'd make sure you needed it
I run a small and a medium sized xpac on the top and the middle of my muskeg along with a nalgene holder on the hip belt, I like this set up keeps it simple and sleek without a ton of pouches everywhere.
I run a medium Kifaru pockets on left side of the belt for trail snacks, headlamp, cell phone and sometimes games calls. You could probably get away with a small just as well, I just happen to have mediums and they fit
Tactical tailor H1 accessory pouch also fits well, although I'd Paracord it over Molle because the clips can dig into your legs
I like the medium sized belt pockets over the smalls (I have 4 of each) They don't weigh that much more and I think they are handier to use. I have used both a bunch. I now tend to run 1 medium on my belt instead of 2 smalls. The medium is easier to use on the side of my T1 or T2 for putting a rifle stock in too.
I'm a big fan of pouches. They're relatively inexpensive, so I own a wide variety and that the pouches that make sense for the trip I'm on. I'll even carry a couple of empty pouches in my day pack amd mount them to make room for meat when successful.