Hello guys, I'm looking for a good wireframing tool with the following criteria:

• Preferably a stand-alone desktop application (non-cloud app)
• Preferably open-source, or free, or one-time cost with a perpetual license (no subscription)
• Has lots of stencils (predefined UI components)
• Easy to add new types of stencils (UI components) that I can reuse for different projects

Which tools would you recommend?

Thanks!