A is for Andorian antennae.
B is for Beta III's humanoid society, ruled by the computer system calling itself Landru.
C is for Ceti Eels. They clear out earwax like you wouldn't believe. But they have really bad side effects.
D is for Denobulan wives.
E is for Excalbians. Talking rocks. Bad idea for an alien. Unless they were just masquerading as talking rocks.
F is Federation Science Council.
G is for Gomtuu. Giant sentient pine cone.
H is for Hands. Lt. Arex on Kirk's Enterprise had more than two.
I is for Intrepid. USS Intrepid.
J is for Jupiter, location of the catastrophic failure of the test flight of the NX-Alpha in 2143.
K is for Klingons. THEY'RE BACK!! And they have ridges. And have ships that sound like TIE fighters. Bad JJ.
L is for Last Battle of the Dominion War.
M is for the Matter/AntiMatter Reactor Core. Better known as the warp core.
N is for Narada, constructed using both late 24th century Romulan as well as Borg technology. Destroyer of dozens of Klingon and Federation vessels along with the planet Vulcan.
O is for Outrageous Okona.
P is for Pacifica.
Q is for Quinn. The other Q that wanted to bump himself off. Which led to the Q Civil War.
R is for the Romulan Neutral Zone. It existed from the year 2160 until at least 2387, but after Romulus was destroyed who knows what happened.
S is for the Sisko.
T is for Tycho star system.
U is for Universal Armageddon.
V is for Valkris, Klingon agent who got her hands on classified Genesis Project materials for her empire - and was prompty eliminated as soon as she turned them over.