I have a launch.config named .NET Attach.

  "launch": {
    "configurations": [
      {
        "name": ".NET Attach",
        "type": "clr",
        "request": "attach",
        "requireExactSource": false,
        "processId": "${command:pickProcess}"
      }
    ],
  },

Here are two ways to run it.

  1. CTRL + P to enter a Quick Open command.
  2. Type debug .NET Attach to run the launch configuration.

Or...

  1. CTRL + SHIFT + P to enter a Command Palette command.
  2. Type Select and Start Debugging to run the launch configuration.