5 Array Formulas
They allow you to do complex calculations on multiple ranges. For example, you can use an array formula to do a vlookup that takes into consideration two ranges to look up.
6 Custom VBA Formulas
A great way to fill in the gaps! For example, you might create a custom formula to proper case the values in a cell
7 Manage Data Model
This is basically a Tabular model like the one found iin Power BI but in Excel. Very powerful!
8 Write Query from Table
Write SQL on Excel data! What could be better?!
9 New Query
Load data from all sorts of different data sources straight into Excel. You can then use it in your data model or write queries from it.
EDIT: Oh you mean start with 5, not do 5! lol... I have more