I can think of six main types of lake regimes based on the environment in which they form and exist (this is a generalisation). In the comments to the question it is mentioned lakes in formerly glaciated areas and lakes formed by tectonic activity such as the African rift. A more rare and perhaps spectacular form come from meteorite impacts. To those I would add lakes related to volcanism, lakes formed in karst terrain and thermokarst lakes formed in permafrost and glacial environments.
Glacially formed lakes are caused by either excavation of valleys to form troughs in which lakes form or by damming of water from glacial deposits. In the case of troughs they definitely are highly eccentric to use the terminology of the question. However, lakes dammed by glacial deposits may have various shapes depending on the terrain upstream of the damming. The damming may of course occur in valleys which again results in eccentric lakes. But local topography will in the end determine the lake fom.
Lakes caused by tectonic activity, such as in the extensional regime of the African rift will be laterally constrained by the rift walls and thus primarily also eccentric. Again, it will be the shape of the terrain that decides the shape so with linear tectonic land forms lakes will probably tend to be eccentric.
Volcanic lakes, on the other hand, probably tend to be more circular in shape since they form in calderas, maars or volcanic craters, all of which are more circular shapes. Some examples include Mono Lake (USA), Pulvermaar (Germany) and Laguna de Quiltoa (Ecuador).
In karst terrain lakes may form from collapse of caves forming water filled sink holes such as Crveno Jezero (Croatia). These are often more circular in shape due to the collapse structure.
The final environment is the cryospheric regions where frozen ground thaws and creates depressions that fill with water. The depressions largely grow radially due to the heat captured by the water of the lake "eating" into the sides of the lake. These types of lakes are common place in Alaska, northern Canada and northern Russia and easily found by a quick browse in Google Earth.
Impact craters form more or less circular lakes if they fill up with water such as Lonar Lake (India). However, sometimes the centre of the impact is uplifted leaving lakes that form a ring such as in the case of Lake Manicougan (Canada) and Lake Siljan (Sweden).
I am sure one could add more instances where lakes form but in general you need a depression formed either by erosion or tectonics or a damming caused either by deposition or, again, tectonics to form a lake.
So to sum up, the form of lakes depends on the environment in which they appear and the processes involved in shaping the topography. In the case of the comparison mentioned in the questions, the lakes presented (one sea) are all very large and may not be representative for all lakes in the world.
There is no strict definition as to the lower limit to what is considered a lake which makes it difficult to assess all the smaller lakes, particularly thermokarst lakes.
Use e.g. Google Earth to visit the sites mentioned in the text.