We designed the Sheppard Brackets floating shelf brackets to solve the fatal flaw that we have seen in all other floating shelf brackets. All other brackets of this style have mounting holes every four inches or more and when installing them, in order to hit studs, you can not install them wherever you want. You need to shift them over four inches at a time and when trying to center them on a wall that becomes a big problem.

https://www.sheppardbrackets.com/about-heavy-duty-floating-shelf-brackets