A Us for Antimatter.
B is for Berthold Rays.
C is for Cochrane.
D is for Deneva.
E is for Ezri Dax.
F is for the Federation Council.
G is for Giant clones of Spock.
H is for H., McCoy's middle initial.
I is for I. As in "No kill I".
J is for Joanna, McCoy's unseen daughter.
K is for Kang.
L is for Leila Kalomi.
M is for Magnificent Mammaries.
N is for Nyota Uhura.
O is for Odo.
P is for Platonians.
Q is for Quantum portedoe weapon away!
R is for Reegrunion.
S is for Sarpedion.
T is for Tuvok.
U is for Under the Enterprise. From where the cloaked Bird-of-prey fired upon Kronos One.
V is for V'Ger. It came to claim Earth.
W is for Warp core breach.
X is for Xindi-Primate.
Y is for Yridian like the one on DS9 that approached Worf with information about Worf's father in the TNG 2 parter Birthright.
Z is for the Zakdorn.