My mistake. In that case, I have to ask, what do you aim to learn from these topics? They are both contextual questions -- a good palette and a good ellipse exist only in relation to an effect you hope to achieve.
A person does not, IME, set out to make 'a 3x5 ellipse', but rather, sees that an ellipse may be suitable here, throws an arbitrary ellipse down, and adjusts it until it suits the context. Factors such as how bright the ellipse should be, what level of contrast it should have with the background, whether it needs to be animated, and whether it is part of a tile all enter into exactly what shape is used, as well as more difficult to pin down concerns as it's contribution to the overall likeness of the subject / conformity to the particular style of the game, site, or project it is supposed to be a part of.
Similar considerations apply to palettes, and, I think it is reasonable to say, 99% of all art-related work. Examining WIP animations can demonstrate this process.
What I am trying to say is that, when you insist that the context, which is the only thing that makes a given choice meaningful, is excluded from replies, there is, AFAICS, nothing at all that anybody can say about the topic (if abiding by the terms you specify).