A few keywords to help delete a lot of garbage from your email using the filter search. You can search subject or body or everything in Thunderbird and the filter provides VERY quick results.

• Shop
• Sale
• Deals
• 10%, 20%, Cont'd
• Off (covers 20% off but also 'offer')
• Last Chance
• 24 Hours
• 1 Day, One Day
• Extended
• Final Hours
• Today Only
• Ends
• Ending
• Discount
• Super
• Blog
• Notice
• Expired
• Reset
• Recover
• Update
• Only
• Rewards
• Confirm
• Preview
• Happy (this will cover birthday, fathers, mothers, and other holiday messages)
• Vote, Congress, senator
• Savings
• Register
• Thank You
• Gift, Give
• Help
• Run
• Network
• Job
• Career