My son received three, gallon-sized, ziplock bags full of random LEGO's for Christmas. I've been scanning the interwebs for unique pieces in hopes of finding some of the kits and instructions for some of the more interesting (to me) pieces. I've been searching all over and hope to find some direction in this forum. I've attached a picture of some of the pieces which look to be part of a spaceship, maybe. Also, there are some numbers stamped on the inside of a few of them such as AM72433, AM18902, and AM76367. I've searched for these piece numbers as well but I can't seem to track them down.
X-27's comment is correct, I have 40 years of LEGO collecting under my belt, and I have never seen any bricks with a speckle pattern like that.
You might go through the bricks you got, knock off bricks are very easy to spot once you have seen a few. Cheap looking plastic, dull colors, lack of Lego logos (almost every single part Lego makes is stamped somewhere) are all signs of knock-off brands.
If you want to search for sets based off of real Lego parts, try: https://brickset.com/, they have a part catalog of pretty much every set ever made that you can use to look stuff up.
Here is a random part I pulled up to show you: https://brickset.com/parts/74335/mini-antenna-ass-red-bla