RE: Good rain team?
I say go with Kingdra and Ludicolo as well. Kingdra is an excellent weather abuser who can outspeed almost anything in the rain and can dish out huge damage with DD, Outrage and Waterfall.
A Rain Dancer might be useful in some cases, but in my opinion it's not always needed. What can prove useful is run a Gastrodon yourself. It can get powered up by your teammates Surfs and is quite bulky, with very high HP. It can learn Rain Dance as well, but that's up to you.
As an extra guy, you can try Rotom-W. It's bulky as well, and benefits from Rain in both STAB Hydro Pump and STAB Thunder.
Another thing you might need is run a flyer, perhaps a Hurricane user, or run Ice beam in your water types for potential Grass threats.
Trick Room strategies now... They can definitely prove threatening, but remember this: in most Trick Rooms, the second opposing Pokemon often uses Protect during the Trick Room setup. This leaves the Trick Room setuper vulnerable to attacks. And since Trick Room always goes last, landing two STAB, Rain-boosted Hydro Pumps might as well take it out.
Finally, electric attackers. Although, as bacon pointed, Discharge makes LightningRod useless (partly), it's still a good idea to run one. It will deal with enemy Thunder users, and dish out a lot of damage itself with its own Thunder. If the opposing electric isn't flying, then Gastrodon takes its pick. Otherwise, if it's a Thundurus for example, just fire your Hydro Pump at it. Both Kingdra and Ludicolo can OHKO in the rain with good nature and EV spread.
Apart from these, however, there's a whole array of strategies to try with Rain. Vaporeon, Gorebyss, Thundurus, even Kabutops or Relicanth are all to be considered
DNA said:
Rain is a very versatile weather; you can do all sorts of things with it.
That says everything.