Liberal parties in Germany

On the occasion of a debate on the similarities between the FDP and NEOS, let me note:

The FDP is "the" liberal party in Germany, NEOS is "the" liberal party in Austria, and both parties are members of the ALDE at the European level. These are the similarities. Since one takes an analogous position within the party landscape, one believes or believed to belong together. In fact, I think there are differences. Historically, the FDP has mostly been a majority buying party, sometimes for the CDU, sometimes for the SPD.

There are at least two other parties in Germany that I would call liberal, namely the "Party of Reason" and the "Party of Humanists". Unfortunately, too little is still known about them, except for those who are particularly interested in politics, and therefore they have no chance in elections.