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

Thunderbird, Postbox

Insert

Show Insert Menu

Show Insert Menu

Compatibility: Thunderbird, Postbox SeaMonkey

Message

Show the Message Menu

Show the Message Menu

Compatibility: Thunderbird, Postbox SeaMonkey

Message Pane

Toggle Message Pane

Show/Hide the Message Pane.

Compatibility: Thunderbird, Postbox SeaMonkey

New Event

Add a new event to the calendar.

Add a new event into the calendar.

Compatibility: Thunderbird, Postbox SeaMonkey

Next Message

Get Real Next Message

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

Compatibility: Thunderbird, Postbox SeaMonkey

Open in Conversation

Open current message in Conversation

Open the current message in a conversation tab

Compatibility: Thunderbird, Postbox SeaMonkey

Options Menu

Show Options Menu

Show the options menu in the compose mail window.

Compatibility: Thunderbird, Postbox SeaMonkey

Paste As Quotation

Paste as a Quotation

Paste text so that it appears as a quoted message.

Compatibility: Thunderbird, Postbox SeaMonkey

Plain Text Paste

Paste Text With No Formatting

Paste text into Thunderbird without any formatting.

Compatibility: Thunderbird, Postbox SeaMonkey

Read

Read Message

Open the currently selected message in Thunderbird.

Compatibility: Thunderbird, Postbox SeaMonkey