1. The following letters can be followed by the same four letters, in the same order.

E _ _ _ _
F _ _ _ _
L _ _ _ _
M_ _ _ _
R _ _ _ _
S _ _ _ _
T _ _ _ _

2. The following letters can be followed by the same five-letter word.

C _ _ _ _ _
F _ _ _ _ _
H _ _ _ _ _
M _ _ _ _ _ 
S _ _ _ _ _
T _ _ _ _ _
W _ _ _ _ _

Answers:

1. Each letter can be followed by IGHT to form a word. 
2. Each letter can be followed by the word ALLOW.