Email cardtype, tform has +subject (Phrase), +body (Basic), +to (Pointer, autocompletes on *account cards). "Magically" has send button. Once it is sent, that button disappears, and those fields become locked. Also includes virtual card: +date sent.
Other possibilities: +attachments (Pointer of file/image cards), offer/expose more headers, etc. Once we implement Pointer validation, +to could also validate on *accounts cards and email addresses (hrm, this latter sort of raises the question of Pointers to non-cards, though it could be special-cased). When we implement groups, +to could autocomplete and validate on groups of *account cards as well. (needs wql extension to be able to find only Pointers in which the cardtype of every is such-and-such?)
+discussed in support tickets+relevant user stories