Any program for conformational searching for sugars?
Use RDKit

It sounds like you're only considering free or open source conformer generation tools. In that case, I highly recommend using RDKit, since the distance-geometry (and in turn ETKDG) methods will intrinsically generate all possible ring geometries. That includes not just the two chair forms you indicate, but all possible ring-puckering forms.

There are other free tools which do this, but RDKit has been repeatedly shown to be the best or among the best free conformer generation tools. (Based on current benchmarks.)


"High-Quality Dataset of Protein-Bound Ligand Conformations and Its Application to Benchmarking Conformer Ensemble Generators." J Chem Inf Model 2017 57, 529-539.
"Freely Available Conformer Generation Methods: How Good Are They?" J Chem Inf Model 2012, 52 (5), 1146–1158.


I'd advocate the newer ETKDG method with RDKit, since it seems to produce somewhat better geometries.