In Sketch, when you have a bunch of layers that need to be converted to symbols you have to select them one by one and use the 'Convert to Symbol' function. Multiple selections will be merged into one symbol. This plug-in will create a symbol for every item that is currently selected. This is really handy when you need to convert a bunch of layers to symbols.
Select the shapes, layers, images, or groups that you want to convert into symbols. Then from the Plugins menu, choose 'Batch Create Symbols'. The Use Layer Names option will create symbols and use the existing layer names. Alternatively, the Use Custom Names option will allow you to add your own name that the newly created symbols will use.
This works by taking the name you enter into the input and adding a number after it for each symbol to be created. For example, if you have three layers, and you enter 'portfolio' as the custom name, each symbol will be named portfolio-1, portfolio-2, and portfolio-3.
Ready to give it a try? Read the install instructions and download from Github.