The top hit on a Google search for "anniversaries" is this list of wedding anniversary gifts from the Chicago Public Library. It includes both "traditional" and "modern" options.
The traditional first anniversary is "paper," the modern is "clocks." Both are kind of tepid.
The "modern" list features diamonds at the tenth, thirtieth, sixtieth and higher anniversaries. The "traditional" list only has diamond at the sixtieth anniversary, which, given lifespans in older eras, seems like a dodge designed to get you out of ever having to give a diamond anniversary gift.
Peculiar "modern" anniversaries include the forty-second ("improved real estate"), the forty-fourth ("groceries"), the forty-sixth ("original poetry tribute") and the forty-eighth ("optical goods -- e.g. telescope, microscope").
Most impressive is that the "modern" listing goes all the way up to the hundredth anniversary, for which the gift is "10-carat diamond." Let's hope you invested properly at the start of that century-long marriage so you can afford the million-dollar price tag.
Overall, I think someone at the Chicago Public Library is yanking our chains.