First of all: This might have been posted already, as it's quite an obvious idea. Didn't find it on first try, just remove this thread if it's not the first one and sorry.
Well: When thinking about new cards, I'd often like to include a passive that gives a creature +x/+x for every copy of it in play. Obviously, Fractal destroys this. At the same time, something like "Can't be targeted with Fractal" is not something one wants on a card. But how about a new passive then? That passive could be called "Pack" (Or whatever, I'm no native speaker) and give +x/+x for every copy of this creature on the field. At the same time, "Pack" would also mean "This creature can not be targeted with Fractal".
Example (Not supposed to be a creative card, just to explain the mechanics):
Pack Wolf 3
2/2
Pack: +1/+1
I think something in the line of this would be a great addition to the game, as Fractal has probably destroyed a lot of card ideas so far. Happy to hear your thoughts.