Because shiny locks weren't introduced until Gen 5, every legendary Pokémon in Platinum can be hunted. Without events (or glitching to event-exclusive areas), this includes Giratina, Azelf, Uxie, Mesprit, Dialga, Palkia, Heatran, Cresselia, the Kanto bird trio (roaming), and Regigigas (requires the other three Regis to be in your party). For the Kanto birds, their shininess is determined as soon as you speak to Prof. Oak in Eterna City, so you'll need to save before then if you're bold enough to hunt a roamer (if you are, this video demonstrates the fastest way to hunt roamers).
If you hack or glitch your game so that you can hunt the event-exclusives in Platinum, you also get access to the Regi trio (requires special event Regigigas), Darkrai, Shaymin, and Arceus.
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