Clustering (unsupervised learning) for uneven classes I am looking for an unsupervised method that can see also the points that start to look different from the majority. Which clustering techniques (I use python) can be used for such data sets?

I have tried k-means but as I was expecting it has failed considerably to see such peaks.
You can try with DBSCAN. It's a clustering algorithm that is meant to isolate outliers. You can read more about it here. It's already available in sklearn (documentation here).

If you tweak its parameters correctly, those "extreme" observations should be identified and separated from actual clusters.