  Various proposals for a new $e^+ e^-$ collider operating below 1 TeV are now
under consideration by the worlwide High Energy Physics community. Among these
are the International Linear Collider and the Circular Electron Positron
Collider. We describe high statistics Standard Model background simulation
samples generated with MG5_aMC@NLO for $e^+e^-$ collider studies at
$\sqrt{s}=91,250,350,500$ GeV. Fast detector simulation is performed with
Delphes and DSiD, the detector card for the SiD detector. The samples are
compared with other simulation samples generated with Whizard.
