This is probably the most relevant update; it has a few sample items. Throughout the campaign, I have frequently said the phrase "items or artifacts," as though those were two distinct categories, but that's not really the case. What I was actually getting at is that while there are common, staple items, there can also be rare and powerful artifacts; they are all just items to the game, though. For the most part, items are one-time use, like potions or bombs, but we can also have reusable ones, and there are some passive ones that just bestow bonuses to certain types of minions or a multiplier to specific resource types--don't let these ideas limit you!
Health potions, for instance, are very common; heroes will drop them somewhat regularly, and you'll match them with flesh tiles to collect them. Alternatively, you can also buy them from floors like the Acrid Alchemist. But we can also have rare items that only drop from specific character types or under certain circumstances; they don't all have to be generic usables =).
There are not many items in the game just yet, which is one reason why they were disabled in the demo. I could list a bunch of planned stuff, but if you are asking because you want to know what to avoid designing, then I actually suggest not worrying about it. I know some people will want to wait and see what's in the alpha or beta before they start crafting their rewards, and that's cool; waiting and seeing might give you a better grasp on how the game is balanced or how your item will fit, thematically and otherwise. If you are more comfortable with waiting, then go ahead.
But don't let my future plans step on your dreams! At the end of the first campaign, a couple of backers suggested werewolves. Werewolves are pretty typical fantasy fare, so they were already on my idea list, and they were definitely going to happen at some point, but their suggestion prompted some discussion on mechanics (transforming, day/night), which opened up other ideas and ultimately lead to something more than I had originally planned (a curse-based system with several were-possibilities). Also, werewolves got added a *lot* sooner, because of these suggestions.
My point is that I know people will ask what's already there or what's already planned, but don't let that keep you from suggesting anything; even if it's already on "the list," you can definitely help make it better! Also, if you have multiple ideas to narrow down, this should be a good place for that, as well; I'm sure the community will be happy to workshop each others' concepts =).