Why would there be a separate forum?
You mean for advertising products? That would be the Publisher/Promotions forum.
If you mean for discussing the OGL itself, we've had them in the past. To be honest, the OGL is a pretty short license; there's only so much discussion to be had about it, and even at the height of the OGL's popularity back in the d20 boom there wasn't that much discussion about the license itself - the forums tend to get very little use. Feel free to post about it in 5E or RPG General!