https://www.alfredapp.com (MacOS app)
At first glance, it looks like a clever alternative to Spotlight: when you press a particular key combination, a text box appears through which you can search for files and open applications. But it is also the ability to run commands by keywords or keyboard shortcuts; for example, you can send a lock command to lock the Mac.
The PowerPack opens up a feature that has become indispensable to me - the history of the clipboard. I have no fear of overwriting an important piece of code in the clipboard - Alfred keeps track of clipboard history and provides search by its content. What is interesting, the history does not contain passwords from 1Password.
Another indispensable feature was the Workflows, where you can describe the order of steps to be performed. For example, I made a Workflow that inserts a line with the current date and time in the place of the cursor in the active application (see video; ⌘V “presses” Alfred).