New samples might be added in the future. All standard samples could be found after TensorRT installation in /usr/src/tensorrt/samples. As for now, you can calibrate your model with int8 precision using added option --calib-imgs on custom trtexec app. You can read readme for more information about trtexec.
git clone https://github.com/SashaAlderson/tensorRT.git samples
cd samples/trtexec
make
You can find generated trtexec file in bin folder.