I remember, for example, an awesome tool from Alex Brollo, postOCR,
a js script which corrects automatically most common OCR errors and converts apostrophes.

Where is this? Is it documented in English?

As Alex says, no. And it's a pity.

I really think it is paramount to have a central place (on Wikisurce.org?)

to discuss tools, templates, and procedures, as an international community.

It is a project long needed.

Where should we start it?

Aubrey