I would really second this. Every single day, I receive spam phone calls from unknown numbers. Unfortunately, I cannot simply block unknown numbers, as some calls are valid. However, I note that most spam calls are very similar, with only the last two digits or so changing. Having wildcards for unknown numbers would allow me to list only a few numbers and get rid of 99% of my spam.
I am no developer, but I have used regex before and that would seem rather straightforward to implement, no?
Thanks a lot!