Animated motion along a given path

[vbl2007]

Often when moving an animation, I need to specify the path of the movement - circle, ellipse, rectangle / square, etc.

Such movements are necessary for the movement of the Sun, the flight of birds and insects and other objects. If I use the current settings, get either a torn motion, or there are a lot of key frames.

P.S. I get it. To move in a circle, the ellipse must use modifiers. If someone has examples, I will be glad to see and take note.