You're walking down the street....

[lotrwk]

I would have to say the zombie. The harpy just doesn't look quite scary compared to him
{Rampaging Baloths} or  {Abyssal Horror}

[Agarrita80]

I'll go with the  {Rampaging Baloths} the horror looks strange though.

{Archdemon of Unx} or  {Hypnotic Specter}

[Thetrufflehunter]

In going with {archdemon of unx}.

A man with a {skeletal grimace} or {creepy doll}?

[Black Death]

{creepy doll}

{Ashmouth Hound}or  {Vampire Lacerator}

[Mlerner12]

The hound
{Emrakul the Aeons Torn}, {Ulamog the Infinite Gyre} or {Kozilek Butcher of Truth}

[Agarrita80]

Always gotta pick  {Emrakul, the Aeons Torn} that thing is freaky.

{Vraska the Unseen} or  {Jarad, Golgari Lich Lord}

[Aladormax]

Varska. Simple reasoning if you see her you're dead.
  {Goblin Piledriver} or  {Goblin Arsonist}

[Thetrufflehunter]

Risibly goblin arsonist. I think he is adorable.

{ragamuffin} or {stuffy doll}?

[Agarrita80]

 {Ragamuffyn} the doll is just sitting there( you may have wrong art).

{Worldspine Wurm} or  {Vastwood Gorger}

[Silent1236]

{Worldspine Wurm}. That thing is giant!  Although, {Vastwood Gorger} has such a sick Alien/Predator mouth. Aliens ❤

Old art {Sengir Vampire} or old art {Llanowar Elves}

[Mlerner12]

Varska. Simple reasoning if you see her you're dead.
  {Goblin Piledriver} or  {Goblin Arsonist}

Actually, you have to see her 👀
                                               

[Agarrita80]

Sengir vampire and what or who has that giant of a vein?

{Carnifex Demon} or  {Ruinous Minotaur}

[Mlerner12]

The demon.
{Griselbrand} or }{Avacyn, angel of hope}
Both Pretty mad at you.

[Iandtormentor]

Gislbrand all the way

{Act of Treason} (the angel person) or  {Adaptive Automaton} AKA Zod

[The1337Magician]

 {Act of Treason}
{Act of Aggression} vs  {Traitorous Blood}