Keyconfig extension: Thunderbird

These are example lines you can add to Thunderbird's prefs.js or user.js files to customize keyboard shortcuts. You need to install keyconfig extension first. A similar page for Firefox is available.

Thunderbird General

user_pref("keyconfig.main.xxx_key__Display Attachments Inline", "!][][][ToggleInlineAttachment(event.target);");
user_pref("keyconfig.main.xxx_key__Rewrap", "!][][][goDoCommand('cmd_rewrap');");
user_pref("keyconfig.main.xxx_key__Run Filters on Folder", "!][][][goDoCommand('cmd_applyFilters');");
user_pref("keyconfig.main.xxx_key__Run Junk Mail Controls On Folder", "!][][][goDoCommand('cmd_runJunkControls');");
user_pref("keyconfig.main.xxx_key__Send Unsent Messages", "!][][][goDoCommand('cmd_sendUnsentMsgs');");
user_pref("keyconfig.main.xxx_key__Mark Msg Answered", "!][][][var hdr=GetDBView().hdrForFirstSelectedMessage; GetDBView().db.MarkHdrReplied(hdr,true,null);");
user_pref("keyconfig.main.xxx_key__Unmark Msg Answered", "!][][][var hdr=GetDBView().hdrForFirstSelectedMessage; GetDBView().db.MarkHdrReplied(hdr,false,null);"); 
user_pref("keyconfig.main.xxx_key__Focus Folder Pane", "!][][][SetFocusFolderPane();");
user_pref("keyconfig.main.xxx_key__Focus Thread Pane", "!][][][SetFocusThreadPane();");
user_pref("keyconfig.main.xxx_key__Focus Message Pane", "!][][][SetFocusMessagePane();");

Delete mail marked as junk in the current folder:

user_pref("keyconfig.main.xxx_key__Delete mail marked as junk", "!][][][deleteJunkInFolder();");

"View > Message Body As > Original HTML / Simple HTML / Plain Text":

user_pref("keyconfig.main.xxx_key__View Message Body As Original HTML", "!][][][MsgBodyAllowHTML();");
user_pref("keyconfig.main.xxx_key__View Message Body As Simple HTML", "!][][][MsgBodySanitized();");
user_pref("keyconfig.main.xxx_key__View Message Body As Plain Text", "!][][][MsgBodyAsPlaintext();");

Extensions

MoreButtonsPlus

Toggle between All and Normal headers (same as clicking "View > Headers > All or Normal"):

user_pref("keyconfig.main.xxx_key__Toggle Headers Button", "!][][][ToggleHeadersButton();");