Adobe Illustrator - Paid
This is the most popular and most versatile editing software on the market. It includes many tools that allow users to create icons, patterns, and even work with gradients and gradient meshes.
Sketch - Paid
It’s exclusive to MAC. It’s mostly used for web design, UI, mobile and icon design.
Affinity - Paid
It’s very similar to Adobe Illustrator and has a decent selection of tools although not quite as extensive. An advantage of this program is that it has a zoom of 1,000,000%.