Without cheats or any events they are Moltres Articuno Zapdos And Mewtwo
in Pokemon ruby there are these legendaries: Groudon, rayquasa, regice, regirock, regesteel, latios. (these are without cheats or events)
To get event Pokemon without using cheats or events is simply impossible without trading. If trading is not an option you must attend these events or use a cheat device.
migrate phione from Pokemon ranger
You can get Giratina, Dialga, Uxie, Azelf, Mespirit, Heatran, Cresselia, and Regigigass. through Pokemon ranger you can get Manphy. through past events you can get Darkrai, Arceus, and Shaymin. You can get a shiny pichu through an event, he may not be legendary but its still worth noting.
No, not that i know of.
No, the only way is to do cheats or an event, and there are no more events for Pokemon Heart Gold because there is a new Pokemon game they are doing special events on.
It is a Shaymin (a grass/flying type legendary) obtained only through mystery gift events unless you use cheats.
you had to get alot of them through events or mystery gifts
The only way to get Celebi on Pokemon Pearl without AR cheats is via event distributions. However these events are no longer being held or supported for Pokemon Diamond, Pearl and Platinum.
In sapphire you cant catch it without events or cheats:-)
you can't do that you need a action replay or R4 if you want cheats. or.... you could probably use the events to get legendaries.but i know you can't use cheats without a action replay