I don’t know how many times I’ve tried, but I have (or had had):
15 Wands,
15 Masks (5 duplicates - male NE x 3!)
42 Lollipops
38 Candy Corn
8 Penny Pouches
1 Hallowed Helm
7 Toothpicks
5 Candy Bars
1 Sinister Squashling.
Good luck to you all 
EDIT:
Several times now I have had a Mask and a Toothpick or a Wand and a Toothpick drop, so it seems that you have a small chance of getting two items in one bag. Wowhead does not show either Hallowed Helm or Squashling from the bag 
But they do indeed drop.
Last updated Oct. 28 - 9.10 am.
PS: This is only from my Achievement-hunting main. But no alt has had either Hallowed Helm or the Squashling as yet.