I do not know your budget but here are some ideas.
Silicone masks- Check out CFX they cater to haunts, really great stuff
Gore Galore's Big costumes and creature carts are awesome as well.
If you are looking for inspiration as opposed to products (Request was a bit vague)
Then look outside of the haunt box. Look at Cirque de Solei or broadway shows (Lion king or Starlight express ) they make costumes all the time and have a different perspective than the normal haunted house point of view.
Stilts are a neat idea for haunts and nothing fills a hallway like a stilt monster.
It would be easier to help you if we had a direction, give us a concept and Im sure many more would help.