Nordtast (German). There is no website anylonger (would have been in German anyways).

Neo2 & 3. Mainstream. The new one might be good.

Aus der Neo Welt (AdNW). Imo the currently best layout, for english and german.
http://www.adnw.de/ (it’s in German…)

The cool thing is that they use algorithms to calculate the best movement of the hands, that is: the shortest distance for fingers to move (= use the middle row most); switch hands as often as possible. Hereby every key gets a value, depending on its ease of pressing it. The 8 keys where the fingers normally lay have the lowest value; they then increase going outward. A programm then places the keys in a random position, then calculates the layout’s score ( probability of letter x value of the key). Following two letters are switched and the process repeats. Of course digraphs (like ‘th’) or experimental even trigraphs (german ‘sch’) are taken into regard.