"t5 custom kydex", "Kydex Holster Solutions" and "JM custom kydex" are all companies I have had great experience with. T5 is great for SP01 light bearing options, KHS is great if you want something fully custom with less common light options.
That being said, I only carry my SP01 with a light so that can be fairly limiting. If you are looking for a non-lightbearing option there are tons more options from generally well-regarded companies, to name a few:
ANR Design
NSR Tactical
Legacy Firearms Co
Happy to help with more holster questions if you have specifics, I know carrying an SP01 IWB can be a bit daunting at first.