Import plugin targets for particles and multimedia are called the same name as the project particles.dll and multimedia.dll. Import plugin targets for webkit and gestures are called project name+qmlplugin: webkitqmlplugin.dll and gesturesqmlplugin.dll. Import plugin target for folderlistmodel is called qml+project name+plugin: qmlfolderlistmodelplugin.dll.

Qt's own QML import plugins can be found under /src/imports

Proposed naming:
webkitqmlplugin
gesturesqmlplugin
folderlistmodelqmlplugin
particlesqmlplugin