Do you know the IMLOG2 Excel function?

Recently I've been exploring some more unknown Excel functions. As such I found out there are many functions in Excel to work with complex numbers. One of these is IMLOG2 which performs a base 2 logarithm on a complex number. Feel free to check out this video if you want to learn more: https://youtube.com/watch?v=ODkzawcrf5c

What are some Excel functions you didn't know existed?