These are a ready make selection of some of the most popular buttons from the Custom Toolbar Button Maker

Thunderbird, Postbox

Previous Message

Get the previous message. Unlink the default Thunderbird buttons this just go to the previous in the list, or if shift is pressed, the previous unread.

Install Previous Message

Download Previous Message

Compatibility: Thunderbird, Postbox SeaMonkey

Purge

Delete all junk emails then compact all folders. Quick way to do both at the same time.

Install Purge

Download Purge

Compatibility: Thunderbird, Postbox SeaMonkey

Remote Content

Opens the window to set exceptions for the loading of remote content

Install Remote Content

Download Remote Content

Compatibility: Thunderbird, Postbox SeaMonkey

Return Receipt

Toggle the sending of a return receipt on and off.

Install Return Receipt

Download Return Receipt

Compatibility: Thunderbird, Postbox SeaMonkey

Rewrap

Rewraps the message text

Install Rewrap

Download Rewrap

Compatibility: Thunderbird, Postbox SeaMonkey

Save Attachments

Save Attachments from an message.

Install Save Attachments

Download Save Attachments

Compatibility: Thunderbird, Postbox SeaMonkey

Search Addresses

Open the advanced address search window.

Install Search Addresses

Download Search Addresses

Compatibility: Thunderbird, Postbox SeaMonkey

Search Messages

Open the advanced message search window to find an email.

Install Search Messages

Download Search Messages

Compatibility: Thunderbird, Postbox SeaMonkey

Send & Receive

Send all messages in the outbox and get all new messages.

Install Send & Receive

Download Send & Receive

Compatibility: Thunderbird, Postbox SeaMonkey

Send Without Save

Send message with out saving a copy to the sent folder. If you want this as the permanent behaviour, there is an option in account settings under 'Copies & Folders'

Install Send Without Save

Download Send Without Save

Compatibility: Thunderbird, Postbox SeaMonkey