Citra was the very first 3DS-capable emulator, built for PC. It is currently available on Windows, Linux, macOS, and Android. The Citra team has a wonderfulgame compatibility listwhich even categorizes the supported games on a scale from "not tested" up to "perfect" so that users can see...
LeapSyncServer is a server program that receives data from LeapSync, a 3DS homebrew application, and emulates a DualShock4 controller. This allows you to use your 3DS as a controller for games on your PC that support DualShock4 input, including support for touchpad, gyroscope and accelerometer...