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

Thunderbird, Postbox

Forward Inline

Forward the current message as part of the email.

Install Forward Inline

Download Forward Inline

Compatibility: Thunderbird, Postbox SeaMonkey

Get Inbox

Change the currently selected folder to your Inbox.

Install Get Inbox

Download Get Inbox

Compatibility: Thunderbird, Postbox SeaMonkey

Go

Show the Go Menu

Install Go

Download Go

Compatibility: Thunderbird, Postbox SeaMonkey

Ignored Threads

View all the threads in the current folder that are set as ignored.

Install Ignored Threads

Download Ignored Threads

Compatibility: Thunderbird, Postbox SeaMonkey

Message

Show the Message Menu

Install Message

Download Message

Compatibility: Thunderbird, Postbox SeaMonkey

Message Pane

Show/Hide the Message Pane.

Install Message Pane

Download Message Pane

Compatibility: Thunderbird, Postbox SeaMonkey

New Event

Add a new event into the calendar.

Install New Event

Download New Event

Compatibility: Thunderbird, Postbox SeaMonkey

Open in Conversation

Open the current message in a conversation tab

Install Open in Conversation

Download Open in Conversation

Compatibility: Thunderbird, Postbox SeaMonkey

Paste As Quotation

Paste text so that it appears as a quoted message.

Install Paste As Quotation

Download Paste As Quotation

Compatibility: Thunderbird, Postbox SeaMonkey

Read

Open the currently selected message in Thunderbird.

Install Read

Download Read

Compatibility: Thunderbird, Postbox SeaMonkey