Public datasets that show “cyclical” behavior

Question

I initially posted this question here

https://datascience.stackexchange.com/questions/78139/public-datasets-that-show-cyclical-behavior

but was redirected here. I am looking for any publicly available dataset that has a "cyclical" structure to it (limit cycles), in the sense that if I plot the data in a certain way, a loop becomes visible. A good example of this would be the Lotka-Volterra predator-prey model, which has a very pronounced cycle, shown below. Are there any other good examples that demonstrate this?

Answer 1

Sunrise (or sunset) vs days distant (i.e., 0-183 days) from equinox yields a nice cycle, and if you repeat over many years you see the effects of leap years and leap centuries. US Naval Observatory would be a good source for that, or any of the various calculated times (from many sources) if calculated values are OK.

Other astronomical data have similar cycles.