Cimarron makes a copy of the Colt Lightning in 38/357, 44WCF, and 45 Colt.
Beretta makes their copy of the Colt called the Gold Rush in 38/357 and 45 Colt.
Pedersoli makes a copy in 38/357.
Also you have the IMI Timberwolf in 38/357 and 44M. We sold a few of these but again had some feeding issues,
In rifle calibers Remington makes the 7615 in .223 and the 7600 is available in .270 and 30-06.
DPMS makes an upper for the AR in .223 in a pump action, the Panther Pump.
In firearms that are out of production Universal Made a version of the M1 Carbine in a pump chambered for the 44 mag called the Vulcan. I had one of these but sold it, it had feeding issues.
There was a AK made called the PAR-1 that was a pump action AK-47 made during the AWB.
And I am sure I am missing some others such as the various rifle calibers and models made by Remington. Also Browning made the Browning BPR in various rifle calibers. Savage made the 170. And there are a slew of 22 rimfires.
Why aren't they more popular? Same reason few people drive a Model T, technology surpassed them. Now before you ask why are pump shotgun so popular then, I will answer that as well. The majority of shotgun are fired less than 10 times a year, you can neglect a pump and it will still work whereas a semi-auto needs more care. Also the recoil in a shotgun is actually helpful in working the action, in smaller calibers that advantage goes away. Most pump rifles lack the accuracy found in bolt actions, semiautos, and even lever actions as well.
I am not knocking the pumps, in places where semi-autos have been made verboten they make sense. I thought about buying one of the Remington 7615 for a car gun till I discovered they had feeding issues. (proper R&D could solve that) For SASS I think one of the Colt Lightning copies would be great. Pumps are much like revolvers these days, most people want the newest and most faddish.