Good double types for Platinum and X?

Question

I was thinking of doing a varietion of the monotype challenge with using 2 types.
I'm thinking 3 one type and 3 of the other.
I still need access to surf and fly.
You don't need to give me teams, just two types that goes well with each other.

Comments

So… a dual-type challenge? If you want a balance of good offensive and defensive types, Steel is a must-have. It hits Fairies in X and gives you gems like Lucario and Aegislash. It resists a ton and has decently good coverage. For the other type, Water would be a good bet for overall coverage, access to Fly, Waterfall and Surf, and stuff like Gyarados, Ludicolo, and Greninja.

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But surf isn't a good move on Gyarados. All the best Gyarados sets gen 4 and onward are pure physical attackers.

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Tags, bro. This is in-game, not competitive.

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Ok, that takes  care of X, but would a rust team work in Platinum?
Is there a steel type before the second grass gym?

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You can get a Shieldon if you're lucky. It depends on your Trainer ID.

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And what if it's the spear instead of the shield?
With nothing but water types, I'll have a tougher time against the second gym.
Especially Rosarade.

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Spear? What?

For Grass-types you can catch a Magikarp and evolve it into Gyarados. It won't take as much damage from Grass attacks and has Intimidate. It gets Ice Fang at lv. 32 as well.

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The other fossil is like a spear.  Mold breaker even works like a spear.
Won't have access to that move this early, (be around the 20's at the time).
What about Bronzor? Would that be early enough?

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Cranidos and Rampardos are not Steel-types.

Sorry if I miscommunicated, I meant that Gyarados would EVENTUALLY have Ice Fang. Bite is still decent though. Bronzer would be perfect, actually, and you can get him just east of Eterna City.

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Doctor Disco, put all that info into an answer, I'll allowed you to get the points.
And I already knew they was pure rock types, I just couldn't spell their names.

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Ah, okay :)

Answer 1

Okay so as I've said in the comments, I think Steel and Water would be good for a dual-type challenge, simply because they get useful secondary types, excellent defences and good coverage moves. They can also somewhat remedy each other's weaknesses. The following Pokémon are useful for either their secondary types, their coverage, or their utility.

Water-types

Steel-types

Comments

I forgot to ask.
Should I count Piplup as water, or steel.

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Empoleon's both types, so if you're going for a 3 Water 3 Steel team I suggest counting it as Steel because there are fewer possible Steel-types.