Gaucho

Gaucho is a nifty Electron-based application that allows you to boost your productivity by enabling you to run tasks or commands, as well as launch applications without having to resort to command line trickery.
It can basically run any shell/terminal command supported by your computer's operating system, be it Windows, Linux or macOS in the case of Apple-vetted desktop devices.

Minimalist and attractive app and task runner that requires npm in order to properly function

It does not require any type of configuration, nor does it require installation, but, before you can actually use it, you will have to make sure that npm is present on your computer's system (npm is included in Node.js, and it's probably the easiest way to deploy it).
The utility is capable of handling multiple tasks at once, and it even offers you a straightforward way to organize them in Suites. It boasts a sleek, modern-looking yet minimalist UI which, for an app of this sort, is a very good thing.

Add, organize, run, or delete tasks with the least amount of hassle

Tasks can be executed by simply clicking the "Run" button and, of course, clicking it once more will bring the currently running task to a halt. You are provided with a set of valuable information such as the task execution time and its status, idle, running, successful or failed, each one with an appropriate color assigned to it, namely black, blue, green, and red.
As expected, you can add new or delete already existing tasks, but, more importantly, tasks can be edited with the help of the button from the upper-right corner. Please keep in mind that optionally, you can add a path for various tasks and if, for example, no path is added, then the utility's own execution path will be used as default.
Running tasks is not possible in "Edit" mode, so you'll have to exit this mode by pressing the same, aforementioned button. Quite interestingly, you can also run entire Suites which, as you might have guessed, runs all the tasks, except the ones that are already running, of course.

Uncomplicated yet highly efficient, open-source app launcher and task runner

Last but not least, please bare in mind that all your changes and configuration settings are stored in the config.json and tasks.json files, which, if you have the proper skills, it can be edited, as well.
All in all, if you're looking for a no muss, no fuss task runner and app launcher that looks right, works on all major OSes and is easy to operate, then you definitely should consider Gaucho.