I would rank them in the following order:
1: Picture #2 it is complex enough to fit very well into the line up but not too busy to make it look to wild.
2: Picture #5 A little more complex than my previous choice but it still works well imo
3: Picture #1 Dont know why but it reminds me of one of those inflatable beach balls, which really fits the theme and the chip looks unique
4: Picture #4 Also cool, not much to say other than that I like it.
5: Picture #6 I like the base color with the the spots but I just feel like others work better.
6: Picture #3 Its nice but there is something there that bothers me...
7: Picture #7 For me this chip is too simple and thus it breaks the progression. Non the less its still a beautiful chip, just not as a 1k chip
This is just my humble opinion hope it helped