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

Thunderbird, Postbox

Add Email

Copy Email Address to Address Book

Add a new email address to the address book.

Compatibility: Thunderbird, Postbox SeaMonkey

All Threads

View All Threads

View all the threads in the current folder, not just unread or some other sub set.

Compatibility: Thunderbird, Postbox SeaMonkey

Archive Thread

Send the Selected Thread to the Archive

Send the Selected Thread to the Archive

Compatibility: Thunderbird, Postbox SeaMonkey

Create Filter

Create filter from message

Create a message filter from the currently selected message.

Compatibility: Thunderbird, Postbox SeaMonkey

Delete Events

Delete Selected Events

Delete an event.

Compatibility: Thunderbird, Postbox SeaMonkey

Download/Sync Now…

Run download and sync before going offline

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

Compatibility: Thunderbird, Postbox SeaMonkey

Edit Draft

Edit Saved Draft or Message

Edit a message that you have saved as a draft.

Compatibility: Thunderbird, Postbox SeaMonkey

Forward As Attachment

Forward message as an attachment

Forward the current message as an attachment.

Compatibility: Thunderbird, Postbox SeaMonkey

Get Inbox

Change Focused Folder to the Inbox

Change the currently selected folder to your Inbox.

Compatibility: Thunderbird, Postbox SeaMonkey

Go

Show the Go Menu

Show the Go Menu

Compatibility: Thunderbird, Postbox SeaMonkey