Hello TenToes! The tiles aren't specifically designed in mind for one engine in particular. I personally use Tiled, which allows to create maps based on a given tileset, I've used it for the creation of the promotional work for Pixelarium and it works pretty well. You can also import the maps you create from Tiled directly into Godot ;)
I realized I was actually subscibed to your Youtube and you show your Tiled workflow there! I need to watch that video. Though I'm also interested in learning to use this for making maps: https://led.itch.io/tilesetter
The tiles look great, I'm gonna use them for a small Zelda-like demo game :)