NOTE: The above are only thermal neutron cross sections. I do not have any energy dependent cross sections. For energy dependent cross sections please go to the National Nuclear Data Center at Brookhaven National Lab.
Select the element, and you will get a list of scattering lengths and cross sections. All of this data was taken from the Special Feature section of neutron scattering lengths and cross sections of the elements and their isotopes in Neutron News, Vol. 3, No. 3, 1992, pp. 29-37.
The scattering lengths and cross sections only go through element number 96 Cm (Curium)
A long table with the complete list of elements and isotopes is also available.
These data were entered by hand from the above cited paper. As such some errors may exist.