A is for Antedians. Evolved mongeese.
B is for Berengarian dragons. Never seen on screen, but huge.
C is for Cardassians. AKA Spoonheads.
D is for Deneva flying pizza monsters.
E is for Excalbians. Silicon-based, and curious.
F is for Ferengi Rules of Acquisition. There are 285 of them. So far.
J is for Janus six.
K is for Klingon head ridges. Now you see 'em, now you don't....at least not for another century or so.
L is for Lovely Ladies. There are hundreds serving on the Enterprise.
M is for Matriarchal regime. Starfleet explorers encountered several during their travels.