Moltres, Articuno, Zapdos, Raikou/Suicune/Entei (depends on what starter Pokemon you chose), Mewtwo and Unown (in the pokedex its considered rare).
You can only get a Mareep by using a Wonder Card which is used in Mystery Gift and with the Wireless Adapter that alters the Pokemon inside Altering Cave allowing you to catch a Mareep, Teddiursa, Houndour, Stantler, Pineco, and Zubat (Which is the only Pokemon you can catch without Mystery Gift.).
No, you can catch Entei without catching Moltres.
No it is not possible.
You Can not
you do not..
you really can't catch celebi in a Pokemon game without cheats
You can't unless you migrate by using the pal park...
There is no way to ONLY encounter fire pokemon, there are places where there is a high rate to catch fire pokemon. But there is no place where you can only catch fire pokemon.
U can catch fire pokemon and heatron is there to
You can only catch them in Pokemon fire red.
You cnnot catch it in Pokemon fire red ,but you can catch it in Pokemon Diamond and Pearl.If you want it to be in your fire red,you will have to migrate it from your Diamond/pearl to your fire red.
you can't catch mew in Pokemon platinum you can only get it by cheats, mystery gift, migrate from a Game Boy Advance Pokemon game like fire red, leaf green sapphire, ruby, or emerald version.