I need the kind of holster that can be hung from a cartridge belt style gun belt with the slot cut low on the strong side.

Black leather. Plain and untooled is fine.

I know S&W made a tan one for my 66, but I can't find a similar one for the 67.

Anyone know where to look?

ETA: 4"

The model 66 and model 67 are both K frame and will fit in the same holster if they have the same barrel length.   There were several manufacturers of black leather holsters for K frame S&W revolvers.  The more common brands were Tex Shoemaker, Don Hume, Safriland, Bianchi, Jay Pee and Gould & Goodrich.   Many serviceable revolver holsters can be found on ebay cheap.

When I started in LE in the mid 70’s the Don Hume Border Patrol holster was popular which rode fairly high on the belt which helped the barrel clear the bench seat.   Some holsters had swivels below belt level to permit the easy carry of longer barrel revolvers.   Some of the older design of swivel holsters had cartridge loops on the belt loop.   Early revolver designs used a safety strap which went under the hammer spur and snapped onto the outside of the holster body.   Later holster designs incorporated a thumb safety strap where a strip of theather covered the hammer to provide better retention.

Recent designs dictate a safety thumb snap as Level I retention, Level II incorporate a thumb strap plus an internal trigger guard lock.  Level III holsters have a thumb snap, trigger guard lock or a second safety catch plus require you to tilt the weapon prior to removal.   The Level II and Level II holsters require more training/familiarization to have any decent draw time compared to open top or Level I retention holster.   Most duty belts or commonly known as Sam Brown belts were from 2” to 2.5” wide and could have two layers of leather to stiffen the belt and some of the better duty belts were suede lined

Here is a link to a typical Level 1 security thumb break holster which were commonly used by uniform officers with revolvers.

https://www.ebay.com/itm/Safariland-Black-Leather-Police-Duty-Holster-S-W-Med-Frame-Revolver-4-229/184199255393?hash=item2ae3219561:g:WEQAAOSwhXJeYWt7

See, the permanent belt loop is the problem. Have a nice vintage gun belt with cartridge loops.

I need one that can be undone and threaded through the gun belt slot.

Already have a nice JP.

Western style?   That will be a tough one.  Maybe El Paso Saddlery will have something.  May have to go custom.

There may be some possibilities on eBay.

Some of the older hunter types had a loop that folded down and had a strap
That ran around the front of the holster and snapped in place. You can usually find such holsters for a 4” K frame in junk boxes at gun shows and shops cheap. As noted any 4” K frame holster will fit all K’s. Problem is holsters attached this way can be floppy and hard to get a smooth draw from. If it were me I would trim the loop section off and thread a conventional holster on the belt. Or not use the belt at all and use a conventional belt plus a slide on for cartridge loops if you want them. Old police 12 round loop slides can be found again for 5 or 10 bucks in most used holster bins