I was previously scraping data from the Animal Crossing Fandom wiki. While it's a great resource, the wiki tends to change too frequently, have too many inconsistencies in how data is formatted, and be too unstructured to be a tenable data source for Nook+.
As such, I'm switched to using this spreadsheet, which seems to have a great community built around it and a concerted effort to maintain a current well-structured data source.
The most noticeable changes resulting from this switch are different images and more current information. For example, the recently added Sanrio villagers are now included in the Villagers section and sea creatures are now available in the Critters section.
This switch may cause some previously checked items to become unchecked due to minor differences in names between data sources. You can address this by re-checking any previously checked items that have become unchecked. Once a item with a name change is checked, it should start working as expected again.
In the longer term, switching data sources will hopefully mean more frequent updates of Nook+, as I won't have spend nearly as much time updating scripts to harvest new data from an ever-evolving wiki.
Another new feature, albeit a smaller one, is a new Photo checkbox in the Villagers section used for denoting which villagers you have photos of. If you have Sync configured in Settings, these Photo checkboxes should be synced along with the rest of your data.
Hope you enjoy these changes!