In each set of four or six incomplete words below, the blanks in the first two words can be filled in with the same letters, in the same order. The third, fourth, fifth, and sixth words can also be completed by filling in the same letters, in the same order - but not the same letters as the words above them. The two or three sets of filled in letters can then be anagrammed into a new word. For example, given the clue

FORE _ _ _
_ _ _ ITE
BR _ _ K
SL _ _ K ,

the answer would be

foreIGN
IGNite
brICk
slICk -  IGN + IC = ICING.

In the following clues, the anagrammed words will all have something in common.

1)
     CO _ _ _ R
        S _ _ _ R
DOM _ _ _ TE
       B _ _ _ Y

2)
     P _ _ _ E
        _ _ _ EY
  DE _ _ _
  VO _ _ _ IZE
 EST _ _ _
RED _ _ _

3)
PL _ _ _
     _ _ _ WER
SE _ _ ING
PE _ _ ING

4)
      G _ _ _ E
          _ _ _ Y
HOR _ _ _
         _ _ _ ING

5)
S _ _ _ Y
   _ _ _ ITUDE
   _ _ _ ANIZE
   _ _ _ IC
   _ _ _ MENT
S _ _ _ ING

HINTS:
The first letters in each pair of blanks are:
1) U and I
2) H, C and E
3) A and E
4) L and R
5) A, O, and A

Answers:

1)
    coUGAr
      sUGAr
domINAte
     bINAry - UGA + INA = IGUANA

2)
  pHONe
    HONey
deCAL
voCALize  
estEEM
redEEM - HON + CAL + EEM = CHAMELEON

3)
plANS
   ANSwer
 seEKing
peEKing - AND + EK = SNAKE

4)
    gLAZe
      LAZy
horRID
      RIDing - LAZ +RID = LIZARD

5)
sALTy
 ALTitude
 ORGanize 
 ORGanic
 AILment
sAILing - ALT + ORG + AIL = ALLIGATOR