As a UX/UI designer I use a variety of tools. Different jobs ask for different tools.

#1. Sketch

Perfect for designing digital products. With the different plugins you can adjust it to your own usage. 

sketchapp.com


#2. Adobe XD

Kind of a similar of Sketch. But the difference is that adobe XD has a perfect prototype module within the app. No need for downloading external plugins. Another benefit is, it works great together with the other Adobe creative cloud tools.

adobe.com/xd


#3. Invision

Great prototype tool. Easy to upload online, link the screens and share with clients. Great in combination with Sketch. 

invisionapp.com


#4. Illustrator

A classic, but still the best tool for designing icons.

adobe.com/illustrator


#5. Omnigraffle

A perfect tool to setup up complex flowcharts. 

omnigroup.com/omnigraffl