What about mlpy, shark, mlpack, shogun, orange, elki, HLearn, etc.? There is very much the list doesn't cover (no offense to the list authors---just, there is a lot out there).
Also probabilistic programming stuff: PyMC, Stan, Dimple, Church. Not sure if these are 'lesser known', PyMC is mentioned often, still much less hype nowadays than neural networks.
Thanks for the suggestions. I don't think PyMC3 and Stan are less known, hence did not suggest to add them in the list.
Dimple and Church look good additions. Will get them appended.
Stan is pretty much known in the Bayesian statistic world no?
There are at least 3 Bayesian books in R using Stan.