Using Illuminate/Database outside of Laravel is the best thing you could possibly imagine
I just finished a client's product using Illuminate/Database or Eloquent alone, outside of laravel, using the Capsule composer package from github.com/illuminate/database.
The experience overall was just amazing and I completed the project in a blink! This particular feature from Laravel lets you write elegantly and be bold at the same time; it already adds some protection to your database, so if you are about to start a really small project where you just need some queries to a MySql database with some front end functionality, well your best shot is to try out Capsule.
Initially I was trying with Medoo but I kindda had a "meh" feeling while looking into it. It also had tons of unsolved issues and well, I thought it wasn't worth it at the end. Luckily I googled out if I could use Illuminate database outside without any issues and got into the best possible solution for my project, I totally recommend it.