Modular Terrace Kit MTK2 Red Brick 4-Pot Chimney Square
The third chimney in this set allows for further variation, since it can be used in two ways, not only as the rear extension chimney (as seen in the screenshots), but also as the stacks found either side of the roof about half way up, rather than those on the ridge, quite a common arrangement which changes the character of the buildings completely. The model is set at a notional height for use with the terraces, although you may prefer the rear extension stacks lower.
You can see three in the screenshot: two in between the main chimneys in the completed model, where they're on the back extensions, and the third, by itself, the first from the left of the hree frestanding chimneys.