Magic Items That Improve Versatility

[hymer]

As DM, one should be able to put some items in the game which could help narrow the gap between the tiers a little. I'm talking less about sheer power, and more about options here.
What are some items you like to get when playing tier 4+ to help you? Do you have any houserules or homebrew you use that would provide versatility?
For the record, my group is mostly low to mid optimization, but it's still very noticeable that e.g. fighters can have trouble contributing, specially out of combat.
Thoughts, ideas, comments, etc. are all welcome.

Edit: An example could be the old staple Ring of Invisibility. That would allow the fighter to tag along on a stealth mission, for example.

[Slipperychicken]

Rod of Ropes is a good one.

[OldTrees1]

First is magic items, second is racial abilities/class features/feats/...

Flight, Mindblank, Stun Negation, Daze Negation, Fear Immunity, True Seeing, Miss Chance, Tactical Teleportation, Death Effect Immunity, Freedom of Movement, Extradimensional Storage Space, Dispel, Initative, Special Senses:

Lists of Necessary Magic Items (http://www.giantitp.com/forums/showthread.php?t=187851)

Flight, Teleportation, Extra planar travel, Buffing, Extra actions, Debuffing, Healing, Invisibility, See invisibility (and other detection powers), Shapechange / transformation, Other stuff (summoning, hit incorporal, anti magic)

Mundanity and how to overcome it handbook (http://www.minmaxboards.com/index.php?topic=11381.0)

[mabriss lethe]

There are a few inexpensive items that can help a lot for increased versatility:

- Bag of Tricks: some random handy summoning in a slotless bag.
- Thorn Pouch: some good battlefield control spells in a slotless bag.
- Crown of the White Raven and variants: very flexible maneuver granting gear.
- Rod of Viscid Globs: magic tanglefoot bags with much better range.
- Aberrant Sphere: summons a couple of different aberrations for a will save tax.
- Hammersphere: Instant Spiritual Weapon.
- Gloves of the Uldra Savant: Ray of Frost at will + 3/day grant a weapon the Frost ability. (really good for a precision damage character.)
- Boots of Stomping: A very cheap low level debuff.

[Azoth]

If you trust yourself to gauge acurately making custom magic items can be a huge boost.

I have made items with set soulmelds in them that worked like the Crown of White Raven that have worked rather well.

Also check out Shax Indispensible Havversack. A lot of mundane/alchemical items that can be used to help out mundanes alot.

A personal favorite is the Colar of Perpetual Attendance. Unlimited Unseen Servant...I'll take two and a side of fries.