Assuming some are real and some are fake, my bet is 1 and 3 are fake.

AI, those trees have too many fingers..

I agree with many others, 1, 3, 5 look most suspicious (assuming numbers precede pictures)

Others seem to have heavy upscaling but it doesn't tend to become too patterned. In 1, 3, 5 grass tends to become something like a fractal rather than grass, plus reflections are sometimes off (that is why 2 is a bit suspicious because of a small tree reflection, but maybe it's just hard to see the original tree), and the branches tend to grow from multiple trees at the same time

1. 1. 5. Are AI images I'm pretty sure, a lot of odd hashing of lines in some of those distant trees.

1, 3, 5 are all fake. Rest are real, including 0.

1,3 and 5. They have that weird pattern in the grass and trees. However, it's getting close. I think soon most people would never be able to tell.

You gonna tell us the answer?

1. Fake

2 . Real 3. Fake 4. Real 5. Fake 6. Real

My guess is they're all real except #5. That one doesn't have as many good reflections off the water.

0, very good, but I feel the grass on the bottom left is off (see comment on 6, probably real)
1, the dead grass on the right looks off
2, the trees to the top left look shifty 
3, the dead sedg/grass in the center looks too even
4, might be real
5, the dead grass again looks off
6, same location and time as 0, either the same seed or real

1. Is definitely AI

About the rest I'm not sure. 3. and 5. look a bit suspicious

I guess 5 and 6 are real

With the HDR effect added to these it's honestly difficult to tell which are generations and which are just heavily post processed

All real?

The only one that looks like AI to me is 2

5 is the only one that looks real to me.

Only 4 looks real to me. Rest AI

1, 3, 5, and 6. The grass is all funky on 1, 3, and 5. The tree and grass on the far left side of 6 is all smeared and stretchy.

I think its AI on 1,5, & 6