Damn. I love the thread, but I wouldn't know where to start. I've been playing D&D for 25 years and at one point or another I think I've come across just about every piece of broken/op stuff in the game. Hell, I ran what was probably the first live-action 4E game ever,
for the game developers, at GenCon UK when they previewed it (I got advance copies) and told Bruce Cordell about a serious RAW exploit I found in the first hour of reading.
Didn't make me hate it less though.
There's just so much stuff, quite aside from the basic equipment you can use for unintendedly powerful effects. Spells which can be cast into an anti-magic shell, infinite power loops (Artificers FTW!), how to make shadow illusions which are more than 100% real, how to give a party infinite actions in a combat round, how to make a thrower build that can take down a great wyrm in a full attack action by L11, which spells are actually good (status effects >> damage)... hundreds of things, all of them using the rules as written

Of course, you don't do that stuff in a PnP game unless by agreement, but as the person who invariably ends up running campaigns I love it when players come up with clever stuff.
Guru-Meditation wrote on Apr 16
th, 2014 at 11:08am:
How so?
Think about it. Shrink Item makes big, bulky things into little, light things, lasts for a day per level and doesn't require a caster at the other end to undo the magic. It has massive implications for the economy. Can you *imagine* the effect that would have on, say, the ability of merchants to get goods into the city quickly and without spoiling? Or the ability of an army to move wagonloads of equipment around? Or how quickly large buildings or city walls could be constructed if you could carry large blocks of stone as small pieces of cloth? If you can shrink a burning fire and its fuel (the example given in the original spell text), the definition of "a single object" is obviously quiiiiiite broad. There are millions of possibilities.
I had a mage/thief in 2e who used to use it as an assassination method. Works very well with anything which can be swallowed whole, bearing in mind that the caster of a spell can always dispel their own magic with no chance of failure...