Many emails I get can't be blocked on Yahoo but I have found if I go to "view raw message" and make filters using their email address domain and "return path" domain and say I want them to go to Trash. You can do this without opening up the actual e-mail because just opening an email to unsubscribe can send a message back to sender by "return path" indicating a valid email address. This has really cut spam out of my accounts. I never get more that 5 spams a day now and most days I don't get any at all. I concentrate on filtering the "domain" not the 20 letter gibberish they use as the name of the person/business email address. It is crazy but I never find any new messages that I have filtered in the actual Trash, I just don't get them anymore.

I have set it up on my iPhone for all calls/texts that are not in my Contacts get filtered to Unknown Senders and do not ring and bother me. I just say if someone needs to get in touch with me they can still leave a voice mail. I use these two sites to look up phone numbers and then I block the number on my iPhone.

Phone Validator: https://www.phonevalidator.com/index.aspx Will tell you if it is a landline/cell/VOIP call.

Spy Dialer: https://www.spydialer.com/ What is cool about Spy Dialer it can even let you hear part if the callers voice mail.

Many texts use "Short Codes", this site can tell you who these "Short Codes" belong to. 88022 - RNC Candidate Donations, 43367 - DNC, etc.