General:

AddressBookAfterSave
AllowDeliveryNotes
AllowHTMLColors
AutoMailCheck
ButtonRowLocation
Buttons
CustomWords
FastLogin
FileUpload
HeadersOnlyLimit
MessageLimit
MultipleAttachments
NoFastLogout
NoInlineImages
NoOnMouseOver
PreferPlainText
Timeout
VCard
ViewSource

Composition:

ComposeBodyColumns
ComposeBodyRows
ComposeFieldWidth
DefaultCC
DefaultBCC
ForwardBodyPrefix
ForwardSubjectPrefix
NoMessageAdvertisement
QuoteChar
RedirectBodyPrefix
RedirectSubjectPrefix
ReplyToAddress
ReplyAllBodyPrefix
ReplyAllSubjectPrefix
ReplyBodyPrefix
ReplySubjectPrefix

Colors:

ALinkColor
AltTextColor
BgrColor
HdrBgrColor
HdrTextColor
LinkColor
TextColor

HTML:

BigTextStart
BigTextEnd
CommonStyleSheet
GeneralButtonSize
MessageLinkStart
MessageLinkEnd
ReplyRowStart
ReplyRowEnd
SmallTextStart
SmallTextEnd
TButtonStart
TButtonEnd
TableWidth

Message headers:

TextAttachments
TextBCC
TextCC
TextFrom
TextPriority
TextReplyTo
TextSubject
TextTo

Statistics:

AdClicks
AdImpressions
LoginCount
MailboxSize
ScreenDepth
ScreenHeight
ScreenWidth
SoftwareVersion