Function XPLMGetNthPlugin 

pub unsafe extern "C" fn XPLMGetNthPlugin(
    inIndex: c_int,
) -> XPLMPluginID

XPLMGetNthPlugin

This routine returns the ID of a plug-in by index. Index is 0 based from 0 to XPLMCountPlugins-1, inclusive. Plugins may be returned in any arbitrary order.