Sketch: Our goto go-to design tool
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Nucleo: icon management 49€ (one time, optional 49E a year updates we currently don't use)
https://nucleoapp.com/
Other popular tools
Balsamiq:
Quick wireframes/mockups.
Gliffy: Gliffy Online wireframe/work-flow diagram and mockups tools
Figma: Sketch+Invision+avocode in one, both web and native apps.
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