For "Simple Color Pallette" I'd say "The newbie shield", but while the design therein is unique, it's hard enough to replicate accurately that it would botch the Memorable quality.
The trouble is, we're trying to convey a complex concept in a symbol, when nobody ever does that. How does
say "A cola product with a high concentration of sugar but which is the rival to Coca-Cola and the choice of a younger generation"? Only by association.
Thus, we'd need to not only forge a new logo, but hide it in every world so insidiously that it becomes The logo. The same way the Triforce shows up everywhere in Zelda, the same way every Pepsi can has the logo, and every McDonalds product bears the M even when they can't fit the rest of the cDonalds.
Ideally it should be something preexisting, like the Grail emblem. But it doesn't have to be, because all the preexisting logos are kinda...ambiguous. "A cup? What game's A cup?" "A ying yang?" "A red sword?" "A shield with some weird japanese writing on it?"
Geometric Logos: Circle with a sine wave. Triangle with an inverted triangle. Triangle with an O in it...
Mascots: Yellow man running. Bee buzzing in a wavy path. Dauchsand mother with 4 puppies. None of these have anything to do with the game, they're just fun. My logo has nothing to do with my business;
Typographic solution: Colorful letters on a white background (Google, Ebay). Two tone letters and background (UPS, Netflix). I'd suggest Tempus Sans ITC, but as has been pointed out, Graal's identifiable "Blue Shadow" style doesn't hold up well with white-on-white. Green text then? Or will it have a green background everywhere it goes?