Please take a look at the attached screenshot of a domainer's offer to sell single character IDNs, for instance an IDN variant (lookalike) of the ASCII character X, which sets a harmful trend. This is an issue if confusability.
I understand that the Registries (are required to?) maintain a list of harmful names for their TLDs, but there is no common minimal list of harmful names. One possible way to achieve this is for the Registries, at least in the ASCII space, to volunteer to feed their respective list of harmful names into a common Registry Stakeholder database, and then draw up a common minimum list of harmful domain names that any Registry could avoid registering.
If At-Large could shape this as a workable suggestion, it could formally go to the Registry Stakeholders.
Sivasubramanian M