Art Studio is a work in progress as the developer told me that he was working on an update to include Apple pencil. RoughSketch converts a photo to b/w sketch for illustrator enhancement. Disregard Glowdraw, Autograph, SPHD, ZB and Drawing Pad. Strip Design and Comic Life are for doing comics or photo jokes. They are updated and work, CL has more frills like themes. Procreate is art for Apple Pencil and a bit cumbersome but is nice. Graphics, Concepts, Sketchbook, and 53 Paper can either be freehand drawing up to drafting designs. There are varying options and myriads of tools. Concepts and Paper53 rock for DIY's and budding artists, you are not required to be pc-tied like Autodesk's Sketchbook or the segmented Adobe which is more for bigger corpo-stuff.
A couple of honorable mentions are Zoomnotes and Goodnotes for your stylii and involve photos and pdf markups and such. Even the little quick-and-dirty free Notes Apple app is weighing in with a drawing upgrade. It even sports a virtual ruler! 9.3 may even give it encrypted password upgrade or maybe 10.0 in the autumn.
For notetaking, Notability stars as well as the last 2 and Microsoft's is also very good if you are in a Windows system. Pigment is an adult coloring app you can get vetted drawings for. You use your stylii with it.