If I remember correctly, the T-34 and M4A3 are the only ones with markers for tank riders, since they had experimented with the idea and abandoned it at some point between vCoH2 and WFA.
The Bren Carrier has seated passengers with new attrib entries, but unfortunately it also requires models to have the right markers.
It's not within the vanilla game but it's still very much within the mod files. You can add it to almost any tank and light vehicle, using the marker_ext within EBPs.


Shoutout to Eebies for the help figuring out that basically any vehicle can carry troops on top.
Finally found this again. Do note that he says
almost though, @Ragnar. It also doesn't look the best for some vehicles, but this is the best the game has to my knowledge.