You shouldn't find any brand that does not list this dimension. The term "effective" is a misnomer and not always used. If a drawing is also supplied, it will be the horizontal TT length, which intersects the seat post, rather than the seat tube.

The TT length alone is NOT enough to define the reach of the frame. Both the TT length and the seat tube angle are needed to define the reach, since each degree that the STA is steeper, increases the reach by about 1cm (with the saddle in the same position, relative to the BB).

The stack concept eliminates errors due to fork length differences between brands. Unfortunately, it references the top-center of the head tube, so you still have to know the minimum headset stack height to have all the necessary fit information.

The manufacturer's listed reach also has a problem. It can only be compared accurately to other frames with the same stack height. If the stack heights are not the same, then a correction of 3mm for each 10mm of stack height difference needs to be applied. For example, you may see two frames from the same manufacturer, where a 54cm and 56cm have the same reach, but the stack height on the 56cm frame is 2cm taller. The reach is not really the same. Subtract 6mm from the reach of the smaller frame and that's the reach at the same stack height as the larger frame.