Before the creation of the IRS, the largest share of federal funds usually came from tariffs imposed on imports. Today, tariffs bring in very little income but are useful for helping to protect certain industries in the United States from foreign competition and to exert diplomatic pressure on other countries.

When the federal government was faced with crises and strapped for cash, it also relied on excise taxes. The most popular and profitable excise taxes were levied on alcohol. Hamilton recommended that an excise tax be imposed on whisky in Federalist no. 12. It was the outrage over this tax that lead to the Whiskey Rebellion in Western PA in 1791. The Civil War was largely funded through excise taxes on all sorts of consumer goods. Excise taxes were and still are taxes that are imposed directly on the sale of certain products (such as alcohol, tobacco, and gasoline), but they make up a considerably smaller share of federal revenue than they did in years past.

Congress's power to impose tariffs and excise taxes is included in Article I of the Constitution, so the exercise of those powers did not require the 16th Amendment to be operative.

There was a thread on this 5 months ago: Before passage of the 16th Amendment and enactment of a federal income tax, what taxes did the federal government levy?

I posted a lot about property taxes in the early US, more just because not many people know about them. In a later reply, I mentioned finding a document, but it's on Wikileaks, so great googly moogly! don't you dare Google for "U.S. Federal Government Revenues: 1790 to the Present"! I asserted

the vast majority of revenue up until 1860 were tariffs with a few spikes of public land sales, then 1860-1916 roughly half and half tariffs and excise taxes (mostly tobacco and alcohol; not much income tax even in the Civil War), then the bulk being income tax up to 1943 or so, then the overwhelming majority being income tax.

descafeinado pointed out "The tariff was the principal historical source of federal revenue until the 16th Amendment. If you look at the 1902 census data, (page 56 of the pdf linked below) for instance, tariffs made up just about half of federal revenue, excise taxes on alcohol 38%, and excise taxes on tobacco another 2%." He linked to (http://www2.census.gov/prod2/statcomp/documents/CT1970p2-12.pdf)[http://www2.census.gov/prod2/statcomp/documents/CT1970p2-12.pdf]