Add filter option for "is in group"
The filters are great but it would be a wonderful addition to add an "is in group"; e.g., <email_address> "is in group" <group_name>.
I generally have groups (distribution lists) used for sending emails. I would be great to have a filter that captures these messages (outgoing to or incoming from addresses in a group) and move them to a folder.
As it is now, this requires duplicate entry -- adding an email to a group and adding that email to a filter to accomplish this same thing. Not only is that redundant but it promotes error if they get out of sync.

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Josh Wood commented
Personally I don't want to create individual filters for certain classes of email like Promotions. Id rather group those senders together and then create a filter that will affect all senders in that group.