Are there any magic items that greatly improve insight, or allow a character to discern lies?

Question

I'm trying to plan a module where the players have to get an artifact to tell if someone is lying, like once per day.

But ones that just improves insight by 10 would be nice.

Does anyone know of any?

Answer 1

Headband of Insight

It's in the Adventurer's Vault. Gives a static +4 item bonus to insight checks and has a daily to give a +6 power bonus to a single insight check. Overall that's better than the daily +10 you mentioned.

Answer 2

Discern Lies, the ritual. PH1:

Make a Religion check. Use the result as a bonus to your Insight checks to discern any untruths spoken in your presence during the duration. If anyone aided you while performing this ritual, they can’t help you make the resulting Insight checks.

There are many items which allow you to cast a ritual through them and act as a free focus 1/day. These can be found in Dragon 387, if you want a model.

If you want an item that can perform what you want, it should be a level 6 uncommon, property: grants the owner the ability to use the discern lies ritual as if they had mastered it and have trained religion. (Net +16 or so to insight checks).

Daily: Perform the discern lies ritual for free.

Answer 3

After a quick search through the Compendium, I've yet to find any that have more than a +6 bonus to insight even up to level 30 items.

Still, feel free to houserule your own artifact into the game if you think that big of a bonus is appropriate for your module. That's the spirit of DnD!

Answer 4

Ioun Stone of Perfect Language

Also in the Adventurer's Vault. It includes a daily that gives you a natural 20 on your next insight check.

Answer 5

Zax, Cloak of Kings

An artifact from Mordenkainen's Magnificent Emporium, it gives a static +10 to insight if it is Satisfied or higher with the wearer.