Sketch: Our go-to design tool
Invision: Tool to share designs and create prototypes (25$/month)
Avocode: Tool for the front-end guys to inspect the designs (243$/Year)
Nucleo: icon management 49€ (one time, optional 49E a year updates we currently don't use)
Other popular tools
Gliffy: Gliffy Online wireframe/work-flow diagram and mockups tools
Figma: Sketch+Invision+avocode in one, both web and native apps.