Cups Approved by the US FDA:
= MeLuna Classic/Sport -- Jul 10, 2014
= Femmycycle -- Nov 15, 2012
= Sckoon -- Sep 18, 2012
= Rhea -- May 24, 2012 (defunct brand?)
= Bellecup -- Jun 28, 2010
= Lunette -- Nov 13, 2009
= Alicia -- Mar 05, 2008 (defunct brand)
= (UK) Mooncup -- Dec 26, 2006
= (US) Moon Cup -- Mar 30, 2005
= Diva -- Jul 16, 2002
= Instead Softcup -- Jun 06, 1997 and Oct 05, 1993 (two dates)
= Keeper -- May 06, 1987
= Tassaway -- Feb 12, 1981 (defunct brand)
To see the list for yourself, search for MENSTRUAL CUP at http://www.accessdata.fda.gov/scripts/cdrh/devicesatfda/index.cfm
FDA Approval means that they are allowed to be sold by US retailers. Americans can import non-FDA cups for their own personal use but may not sell them on a retail level.
Edited for clarity.