A Dynamic Cheat Sheet to lookup for Common Core Functions for Reusability

When developing Region or site level codes, sometimes we tend to create our own functions to complete it; But what if there is a core function which does the same thing and you didn't know of.

Below advantages can be achieved if the common core functions are in your fingertips.
REUSABILITY - Can reuse the existing core function without re-inventing.
QUICK - Since not required to write the function or test it, it will save precious time.
ACCURATE - Since it's a core function and tested and finalized, it is accurate.
CONCISTANT - Since going to point to the same function where ever you are, it will be consistent across the system.