Seeking free or low cost software to help manage web based email (e.g., Yahoo or Gmail)?

Tom asked: I have several Yahoo email accounts (and a few gmail, also) for various purposes. The filter service for Yahoo is inadequate. I’m too busy to write the program I need, which would do the following as a minimum:
A) Allow me to define powerful search criteria using nested logical expressions or regular [...]

Gmail email question. Is there any way to set my Gmail spam filter better?

xx0xx asked: I keep getting alot of spam mostly porn or presciption meds. My spam box has over 80 emails within 1 hour. How can i set this up to not get this.
I hate to click on the email, because it may be a keylogger or virus. Thanks.