Any Pokemon you want to.but you cant trade Pokemon you get from events over wifi
you can trade Pokemon from heartgold and soulsilver to your diamond,pearl, or platinum.
you can trade pokemon from heartgold to black but you can only transfer the pokemon in heartgold not trade it from black
You have to trade it to HeartGold from P/D/Pt
yes. you can trade Pokemon from diamond, pearl, or platinum to heartgold or soulsilver.
No, but you can trade Pokemon only in HeartGold to Black
no. itcould trade with emerald. soul silver and heart gold could trade
You can't get regigigas in Pokemon Heartgold. only if you trade.
It's impossible to get it in Heartgold, unless you trade it or migrate it.
You can trade between HeartGold and Platinum as soon as you have gotten the regional PokéDex in both games so HeartGold can trade with Platinum as soon as Professor Oak gives you the PokéDex in Mr. Pokémon's place and Platinum can trade with HeartGold as soon as Professor Rowan gives you the PokéDex.
Rotom is not found in HeartGold so you will have to trade it from another game
AMAN
Trade!