Loads, though some of it depends on how loose a definition of the term federation you want to use.

The Iroquois for example, were a federation of several tribes that banded together for mutual cooperation but obviously maintained their own individual governments and customs, in fact, this is pretty common in tribal socities.

For a stricter definition, Switzerland has been a confederation since at least the 13th century when the various alpine towns started to come together and form groups which would share resources but again, maintain original governments and be free to do whatever they wanted.

The Greek states sometimes formed federations to deal with threats, like the league of Corinth in the 4th century BC.

Once again, unfortunately, the oft quoted uniqueness of the American revolution is not that unique after all.

I'll raise a distinction that I think is (or should be) important.

The other comment here is correct in that history is replete with con-federations. Indeed, if you go even before Rome, you will find the Etruscan League, a confederation of twelve city-states meeting every year at a shrine, the fanum voltumnae, to settle matters of common business. The Delian League is an analagous example from Greece.

The uniquely American contribution was to take the confederation structure -- which has only rarely been conducive to long-term stability and national identity -- and add a strong central government. This is why you hear the Constitution, not the Articles of Confederation, praised as the uniquely American innovation.

That in turn came in response to a relatively narrow set of circumstances. First, the thirteen colonies had comparatively shallow history and a shared foundational identity. They were all, that is, until recently, British subjects. Second, they had fought a war (in some sense) together, giving rise to a background national identity. Third, they had tried the confederation structure, and it had failed.

To focus on point three, the Articles of Confederation were an unmitigated disaster. The central government under the Articles lacked authority to conduct any serious national business, or address problems of nationwide significance, culminating in Shay's Rebellion. Confronting the central government's inability to quash it, Washington wrote:

What stronger evidence can be given of the want of energy in our governments than these disorders? If there exists not a power to check [the rebels], what security as a man of life, liberty, or property?

Chernow, Life of Washington, 518

The modern Constitution was a direct response to the Articles' perceived impotence, vesting the central government, for the first time, with the authority to levy taxes from the states, and (for example) regulate interstate commerce by majority vote.

Unless I am missing something, that at least, a confederation presided over by a strong and vital central government, but crafted to ensure respect for the separate sovereignty of the subsidiary units over all other matters, might be historically unique.