Assume that you need to log some of your readings from the input pins of your Arduino Uno (or MEGA, etc.) dev board which needs to work standalone. The proper way is to store the log in an SD card ...

⛰️The code for an Arduino-based device that records GPS and Environmental Data to an SD card over time while displaying the current values on an E-Paper display.

So you've already outgrown Arduino's most beginner-friendly board, the Uno, and are looking to move on to bigger, more exciting projects. In that case, the Nano family might just be what you need.