This question seems not a best best question for this place but still related. I am doing a project regarding to lidar that involves in testing lidar behaviour when beams get absorbed. So, what is a good off the shelf material that is good on absorbing 850nm-1000nm bandwidth?
You can try thermographic paint. It's made to make the surface non-reflective at IR wavelengths. It's needed to let IR radiate effectively for temperature measurement, but as well it can absorb external radiation. I haven't tested it.
IMO you'd be better to find a planar material that is reflective to IR so that you reflect the beam away from the target and away from Rx.
For example here is the response of ZnSe as an absorption example:
There were some great Lidar shots from Google (I can't find them) that showed just the effect you want. The had a bus in view and the windows were black (no return at all) due to the IR reflectance of the glass. Yet the camera shot showed all the people in the bus. It was a great example.
So almost any heat reflectig glass may do a reasonable job.