Hideaki Nakano (of Detroit) created First Day Covers (and some event covers) from 1980-1989.
Many of these passed thru the hands of Swap Meet Dave.Nearly all of them must be seen to be believed.https://SwapMeetDave.com/Stamps/FDC/Nakano.htm
... FDCs/etc on #6 envelopeshttps://SwapMeetDave.com/Stamps/FDC/Nakano-2.htm
... FDCs/etc on over-size envelopes
But even with that introduction, these two Valentine-style FDCs uh, well, stand out
Extra credit if you noted the "H.N" perfin on the US 22c Love stamp, FDoI 19850417.
Lots of extra credit if you can find those Manama Mother's Day stamps in a catalog
/s/ ikeyPikey (who paid a total of two dollars to a dealer who could not believe his good luck in finally unloading these bizarros)