Tracking task for requests for new constraint types in Wikidata.
Feel free to add this task as a parent for the tasks you find or create on that topic.

According to the 2020 report on Property constraints (T244043), when active editors were asked in December 2019 whether it would be better to develop new constraint types or to improve existing features:

• 47% said both things were equally important,
• 31% said it would be better to improve existing features,
• 17% did not answer, and
• 5% said it would better to focus on developing new constraint types.