If people here are interested to do that, I think it would make a lot of sense to collaborate with existing scion exchanges. My dream is multi-lingual site that collects data on varieties and provides ways of filtering out locations where it might be difficult to send material. Scions are by their very nature something that more growers can more easily get behind and takes less explanation than a seed grex or modern landrace. In francophone Europe, there’s https://www.fruitiers.org/ which is already amazingly diverse. I’m grafting 50 news varieties of stonefruit, quince, red-fleshed apples, hazelnut and all kinds of stuff this year, just from exchanging with colleagues there. A lower-hanging fruit might be to collaborate with fruitiers to help turn the site more multi-lingual or merge it with North American databases - North American Fruit Explorers (NAFEX) has a scion exchange? I think most of them are boomers with crazy collections and just use Facebook.
Apropos, this thread: What if the Landrace Community had a way of swapping seed as effective as this Scion Exchange (based in France)?