Practical insightful time domain functions This question might be a little bit different, but i am having hard time to find some sort of a list/book/website/advice, with very practical time domain functions that provides useful insgihts for a series of numbers in time domain (frequencies of less than 1Hz)

Examples - FFT to find periods in a noisy signal, Autocorrelation  for finding an interesting correlations between 2 curves.

Very curious to know about more, maybe more functionality about prediction and information that is useful and critical in real life.
I've written a series of three blog articles about three families of time domain frequency calculation for single pure tones, real or complex.  You can find them here:


Exact Near Instantaneous Frequency Formulas Best at Peaks (Part 1)
Exact Near Instantaneous Frequency Formulas Best at Peaks (Part 2)
Exact Near Instantaneous Frequency Formulas Best at Zero Crossings


The applicability in DSP is rather limited, but if this is what you are doing, these are the formulas you want.