ELHEAPO, the Phantom Filters will do the trick, but they are going to be more difficult to handle and clean since they are so thin. Glass filters like the DJI, Polar Pro, SRP, and TACO-RC are easier to install, handle, and clean. They will be more durable too since they are made of glass. Whatever filters you choose, make sure you get at least an ND8 and ND16. You'll also want an ND4 if you shoot video early in the morning or late in the day when the sun is setting.
You can find a list of all commonly used Phantom 3 lens filters
here.
To the right of the listed lens filters, you'll see some links to videos/discussions that talk more about some of those filters. It'll give you a better idea of what people think about them.
Here are some of my thoughts on the other lens filters:
SRP: I have a few of these. The quality of the lenses is excellent and the resulting videos. They are a bit tough to slide on and off the camera though.
DJI & TACO-RC: Both weigh the same as the stock DJI UV filter. That means no extra stress will be placed on your gimbal. I'm not sure how important the extra weight of the other filters is since nobody ever complained that their gimbal was damaged to the extra weight. But, it's a point to consider.
Polar Pro: Many people use these -- I'm assuming this is partly the case since they were one of the first to release filters. The reviews are generally favorable. If you decide to buy them, get the
6-pack instead of the
3-pack. The 3-pack doesn't contain all of the filters you'll need, so you'll end up getting the 6-pack later anyhow -- or buying the extra filters you need elsewhere.