Explicitly correlated multireference theories (CASPT2-F12, MRCI-F12) as described in T. Shiozaki and H.-J. Werner, Communication: Second-order multireference perturbation theory with explicit correlation: CASPT2-F12, J. Chem. Phys. 133, 141103 (2010); T. Shiozaki, G. Knizia, and H.-J. Werner, Explicitly correlated multireference configuration interaction: MRCI-F12, J. Chem. Phys. 134, 034113 (2011); T. Shiozaki and H.-J. Werner, Explicitly correlated multireference configuration interaction with multiple reference functions: Avoided crossings and conical intersections, J. Chem. Phys. 134, 184104 (2011) lead to much improved convergence of the correlation energies with the basis set size. Explicitly correlated version of the RS2C and MRCIC codes are not yet available but will be made available as soon as possible.
A review of the explicitly correlated multireference methods can be found in T. Shiozaki and H.-J. Werner, Mol. Phys. 111, 607 (2013).