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

Thunderbird, Postbox

Edit as New

Edit Message as New

Edit an email.

Compatibility: Thunderbird, Postbox SeaMonkey

Get Inbox

Change Focused Folder to the Inbox

Change the currently selected folder to your Inbox.

Compatibility: Thunderbird, Postbox SeaMonkey

Message

Show the Message Menu

Show the Message Menu

Compatibility: Thunderbird, Postbox SeaMonkey

Options Menu

Show Options Menu

Show the options menu in the compose mail window.

Compatibility: Thunderbird, Postbox SeaMonkey

Threads with Unread

View Threads With Unread

View only the threads in the current folder that have unread messages.

Compatibility: Thunderbird, Postbox SeaMonkey

Create Filter

Create filter from message

Create a message filter from the currently selected message.

Compatibility: Thunderbird, Postbox SeaMonkey

Watched Threads with Unread

View Watched Threads With Unread

View watched threads that have unread messages in them.

Compatibility: Thunderbird, Postbox SeaMonkey

Ignored Threads

View Ignored Threads

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

Compatibility: Thunderbird, Postbox SeaMonkey

Open in Conversation

Open current message in Conversation

Open the current message in a conversation tab

Compatibility: Thunderbird, Postbox SeaMonkey

Email Headers

Toggle what email headers show

Sets what headers are displayed for an open message.

Compatibility: Thunderbird, Postbox SeaMonkey