The Dark Shadows Alphabet Game

R is for rocking horse, which did not look right under David Henesy.

S  is for Saber that were on the walls a few times.  Once in a while they were used.

T is for Tom Happer (Jeremy Grimes)

U is for ulster - a long, loose overcoat.  Barnabas and many others wore such a garment.

----- Sally -----

V is for the viewers who tuned in to DS each weekday.

"Welcome to the beginning and the end of the world, Miss Winters." (Burke to Vicki, ep one)

How about....

X is for the x written on the piece of paper near [spoiler]the dead body of Randall Drew?[/spoiler]

Y-yabber to Jabber something or ingage in jabbering

The encircled X (on the list as the symbol on Lorna's forehead, Quentin's ring, and the note near Randall) should probably be retired now as an answer for that letter. 

A is for alienate [spoiler]like Julia alienated Barnabas when he learned of her hypnotizing Vicki against him, or Barnabas alienating Roger when he accused David of stealing Ezra Braithwaite's ledger.[/spoiler]

The list already includes zombie army, zombie, and zombify.  Sorry, but another Z word is needed.

Okay...

Z is for zygomatic arch (aka the cheekbone).  Several castmembers had stunning cheekbones, especially Grayson Hall. 

B

Broomstick (Burke suggests it to Vicki as a suitable mode of transportation for Collinsport in ep one)

C is for culprit there were many of those, Jason, Barnabas, Willie .....

D is for the devil's mark.