Mac: Apple might have pulled the battery life indicator out of the MacBook, but there are plenty of third-party ways to bring it back. If you're looking for something a little more fun than just a number, Juice let's you set your own customisable icons for different battery levels.
Instead of a boring old percentage indicator, Juice shows an emoji, some ASCII art, a string of text or a few other options. You can edit those options with pretty much whatever you want by editing a single plist file, which means you can change what appears in the menu bar for each percentage of battery life to whatever you want. That sounds complicated, but it's actually pretty easy to edit to make your own indicator. Regardless, Juice is packed with some fun options, even if you don't want to make your own.