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

Thunderbird, Postbox

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

Account Setup

Run Account Wizard to set up a new account in Thunderbird.

Install Account Setup

Download Account Setup

Compatibility: Thunderbird, Postbox SeaMonkey

Detach Attachments

Detach Attachments from an email.

Install Detach Attachments

Download Detach Attachments

Compatibility: Thunderbird, Postbox SeaMonkey

Go

Show the Go Menu

Install Go

Download Go

Compatibility: Thunderbird, Postbox SeaMonkey

Reply to Sender Only

Reply only to the sender of the email.

Install Reply to Sender Only

Download Reply to Sender Only

Compatibility: Thunderbird, Postbox SeaMonkey

Archive Thread

Send the Selected Thread to the Archive

Install Archive Thread

Download Archive Thread

Compatibility: Thunderbird, Postbox SeaMonkey

Delete Events

Delete an event.

Install Delete Events

Download Delete Events

Compatibility: Thunderbird, Postbox SeaMonkey

Delete Tasks

Delete a task.

Install Delete Tasks

Download Delete Tasks

Compatibility: Thunderbird, Postbox SeaMonkey

Download/Sync Now…

Runs the download and sync now tool, so that messages can be used when you go offline.

Install Download/Sync Now…

Download Download/Sync Now…

Compatibility: Thunderbird, Postbox SeaMonkey

Forward As Attachment

Forward the current message as an attachment.

Install Forward As Attachment

Download Forward As Attachment

Compatibility: Thunderbird, Postbox SeaMonkey