Welcome to TreasureNet! All I see is natural rocks -no artifacts. Keep looking fellow there's plenty of good stuff out there waiting to be found. Good luck.
I have to agree with the others. Nothing you have shown shows any evidence of ever being altered or utilized by man. They are all naturally eroded stones.
Like the others have stated they are all natural. Mother nature can fool you big time until you get your eyes trained in what you are looking at. Welcome to T-net
Keep looking! You have the eye for spotting stones that could be artifacts so you will eventually find some. Unfortunately these rocks look naturally shaped and not altered by man. Good luck!!