I need help finding Pokemon (for the national dex, not to own them) If..

All those Pokemon cannot be seem from trainers.
Rotom, Regigigas, Heatran, and Giratina are all one-of-a-kind. You're required to battle them, and you're only given one chance, so you may wanna catch them.

1. Rotom: Found in the TV in the Old Chateau at night.

2. Froslass: Give a female Snorunt the Dawn Stone.

3. Electrivire: Trade an Electabuzz while holding the Electrizer, found from wild Elekid in front of the Valley Windworks when FR is inserted in the DS.

4. Magmortar: Trade a Magmar while holding the Magmarizer, found from wild Maby in Stark Mountain or on route 227 when LG is inserted in the DS.

5. Regigigas: Requires you to transfer the 3 Regi's from Ru/Sa/Em. Then, deep in Snowpoint Temple will be the "king of the three", level 70 Regigigas.

6. Cresselia: The only legendary besides Mesprit that doesn't require to be caught to be seen. Talk to Sailor Eldrich in Canalave City and he'll take you to Fullmoon Island, and there, you'll see a picture of Cresselia, and then she'll run off in the wild grasses of Sinnoh.

7. Magnezone: Train a Magneton in Mt. Coronet.

8. Lickilicky: Train your Lickitung while he has rollout in his moveset.

9. Rhyperior: Trade your Rhydon while holding the Protector.

10. Tangrowth: Train your Tangela while he has ancientpower in his moveset.

11. Yanmega: Train your Yanma while he has ancient power in his moveset.

12. Heatran: One of the legendaries. Found in Stark Moutain. I take it you've already been there. Once Buck stone the treasure, go back to his house east of the Pokemon Center in the Survival Area. Then, once you've talked to him there, go back to that room in Stark Mountain and battle the level 70 Heatran.

13. Dusknoir: Trade your Dusclops while holding the Reaper Clothe.

14. Probopass: Train your Nosepass along the side of Mt. Coronet.

15. Gallade: Give your male Kirlia the Dawn Stone.

16. Porygon-Z: Trade your Porygon2 while holding the Dubious Disc.

17. Togekiss: Give your Togetic the Shiny Stone.

18. Mamoswine: Train your Piloswine while he has ancientpower in his moveset.

19. Glaceon: Train your Eevee while he likes you a lot near the Ice Rock on route 217.

20. Leafeon: Train your Eevee while he likes you a lot near the Moss Rock in Eterna Forest.

21. Glicsor: Train your Gligar at night while holding the Razor Fang.

22. Giratina: Found deep in Turnback Cave, in Spring Path along route 214.

I just would like to know one thing... How do you know the names of the Pokemon, but not how to get them? It's kinda wierd, don't you think?

These Pokemon are not part of the sinnoh dex. These Pokeomon you get after you get the national dex.

Rotom get national pokedex go to eterna forest at night gym leader will be there talk to her then go inside old chateu and talk to a tv

Frosslass evolves from snorunt with the dawn stone

Electivire evloves by trading it while holding the electrizer which you get from wild elekids

Magmortar is the same as electivire just that it use the magmarizer you get from wild magbys

Regigigas get the three regis with national pokedex then go to snowpoint temple at the last floor you will battle regigigas

Cresselia get national pokedex go to canalave city talk to guy who takes you to iron island he will take you to fullmoon island to get a item talk to cresselia at island it will leave and runaway like mesprit and you will find lunar wing after cresselia leaves

Magnezone train it at mount coronet


you have to level lickitong up and it has to know the attack rollout

Rhyperior you have to trade it while holding the protecter


Train tangela while knowing the move ancient power


Level up yanma with the attack ancient power known

Heatran find at stark mountain after you get national pokedex

Dusknoir trade dusclops while holding reaper cloth

Probopass level up nosepass at mount coronet

Gallade evolve male kirlia with dawn stone

Porygon z trade porygon two while holding dubious disk

Togekiss evolve trogetic with shiny stone

Mamoswine level up piloswine with ancient power known

Glaceon train eevee near snowpoint where you find frozen stone

Leafeon train eevee at eterna forest near moss covered rock

Glicsor train gligar while holding razor fang at night

Giratina get national pokedex then go to spring path above pastoria city take spring path to turnback cave take rock smash surf and defog

You need the national pokedex for mostly all of the Pokemon you chose

1. Rotom-Requires capture. Found at the Old Chateu's TV, located on the second floor, next to the room with Gengar. It can only be found at night, and is at level 15(bring a weak Pokemon, as you will have but one chance).

2. Froslass-Migrate a female Snorunt from R/S/E, then use a Dawn Stone on it.

3. Electivire-Trade an Electabuzz with an Electrizer held.

4. Magmortar-Trade a Magmar with a Magmarizer held.

5. Regigigas-Migrate Regirock, Regice, and Registeel and have them in your party, then go to the Snowpoint Temple and make your way to the top, one you solve the ice puzzle, talk to the "statue" and it will battle you at level 70.

6. Cresselia-After getting the National Dex from Oak, go to Canalave and talk to everyone in the sailor's house. This activates the event, so now, talk to the sailor and he will say something, now sail to Fullmoon Island. Go talk to Cresselia, you will get it's Pokedex data, then it will fly off, leaving the Lunar Wing. Take it back to the little boy in the house and then he will wake up. Now you can use your Marking Map Poketech App. To track Cresselia(it's at level 50).

7. Magnezone-Either find the Magnemite Swarm(it is at the Feugo Ironworks) by talking to TVs regularly, or migrate one from R/S/FR/LG/E. Then train it to level 30 and evolve, and lastly, take it into Mt. Coronet and make it level up and it will evolve into Magnezone(ONLY IN MT. CORONET!).

8. Lickilicky-Migrate Lickitung or find a Swarm, then teach it Rollout and make it level up.

9. Rhyperior-Catch a Rhydon(or migrate one), grab the Protector in the sandstorm route(above the Resort Area), then make Rhydon hold it, then trade it.

10. Tangrowth-Level up Tangela with Ancientpower.

11. Yanmega-Level up Yanma with Ancientpower.

12. Heatran-Go to Stark Mountain, team up with Buck, get to the end and he will take the Magma Stone, then use an Escape Rope, go to the survival area and look in the houses, when you find Buck, talk to the guy next to him, then talk to him. Go back to the end of Stark Mountain and you can battle Heatran at level 70(you only get to battle him once, like most other legends, so be sure to save beforehand).

13. Dusknoir-Trade a Dusclops while the Reaper Cloth is held.

14. Probopass-Level up Nosepass in Mt. Coronet.

15. Gallade-Use a Dawn Stone on a male Kirlia.

16. Porygon-Z-Trade a Porygon2 while the Dubious Disc is held.

17. Togekiss-Use a Shiny Stone on a Togetic.

18. Mamoswine-Teach a Piloswine Ancientpower, then make it level up.

19. Glaceon-Have an Eevee in your party, then go to Snowpoint City and head south into Route 217, now find the white rock and level up your Eevee while next to it.

20. Leafeon-Go to Eterna Forest, find the mossy rock and level up your Eevee.

21. Glicsor-Level up Gligar with the Razor Fang held at night.

22. Giratina-Catch in Turnback Cave at level 70.

Look here, just find their Dex entries.