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

Thunderbird, Postbox

Plain Text Paste

Paste Text With No Formatting

Paste text into Thunderbird without any formatting.

Compatibility: Thunderbird, Postbox SeaMonkey

Previous Message

Get Real 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.

Compatibility: Thunderbird, Postbox SeaMonkey

Purge

Compact Folder, and Delete Junk

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

Compatibility: Thunderbird, Postbox SeaMonkey

Read

Read Message

Open the currently selected message in Thunderbird.

Compatibility: Thunderbird, Postbox SeaMonkey

Remote Content

Set the exceptions for what remote content can load.

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

Compatibility: Thunderbird, Postbox SeaMonkey

Reply to Sender Only

Reply only to the sender of the email

Reply only to the sender of the email.

Compatibility: Thunderbird, Postbox SeaMonkey

Return Receipt

Toggle Return Receipt on/off

Toggle the sending of a return receipt on and off.

Compatibility: Thunderbird, Postbox SeaMonkey

Rewrap

Rewrap

Rewraps the message text

Compatibility: Thunderbird, Postbox SeaMonkey

Search Addresses

Open Addresses Search

Open the advanced address search window.

Compatibility: Thunderbird, Postbox SeaMonkey

Search Messages

Open Message Search

Open the advanced message search window to find an email.

Compatibility: Thunderbird, Postbox SeaMonkey