MolTPC
MolTPC provides a solution for fully automatic tautomer enumeration.
...The few freely available software packages limit their output to a subset of the possible configurational space by sometimes unwanted prior assumptions and complete neglection of ring-chain tautomerism. MolTPC provides an adjustable and fully automatic approach for this problem.
The original publication can be found on http://onlinelibrary.wiley.com/doi/10.1002/jcc.23397/full.