Is this a logo? Because this looks like a custom design. But there are similar casual brush scripts available I'm sure.

It is a logo, but honestly in all my years of rebranding, I've never had a client whose previous logo was a custom job. That's what I do.

Hahahahaha! Frankly, I doubt you're the only one to custom design logos. ;^)

First thing you need to have a look at is Rob Leuschke's work. You can see it here on MyFonts.