The best alternatives to Quill are Pattern, Astropad, and The Omni Group. If these 3 options don't work for you, we've listed a few more alternatives below.
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Astropad will be your graphic design tablet for your Mac! Draw directly, with no compression, in Photoshop from your iPad. This tool allows you to connect your Mac and your iPad together to create the perfect working space! No lagging, only high-quality clear images!