Where I could get these Pokemons?

Togepi and Tyranitar: See my answer to your question on the Pok�mon Fire Red columns; click here to go there.

Mantine: The routes for Qwilfish provided in my answer on Fire Red, but on Leaf Green. It can also be obtained on Colosseum.

Remoraid: A shadow Remoraid can be caught on Pok�mon Colosseum.

To get togepi play Pokemon colosseum and catch the shadow togetic, then trade it to your version and breed it (if the togetic is a girl it'll be a baby togepi). Same thing for mantine, and ramoraid. For tyranitar, go to the seventh sevii island and go to sevault canyon and search the grass for larvitar, it evolves to pupitar at level 30 and then to tyranitar at level 55. Teach it crunch, earthquake, rock slide, and hyper beam for the best results, he learns them all by level, and he automatically summons a sandstorm in battle so that's like an extra attack. He's worth it. Hope you have Pokemon Colosseum.

You get Togepi by hatching an egg received from a man at Island 5. I don't know about Mantine, but to get remoraid just fish at Island 5 with your super rod. To get a Tyranitar catch a Larvitar at Island 7 then evolve it at lvl 30 to get a Pupitar, then evolve it again at lvl 55 to get a Tyranitar. Helpful?

Togepi - can be found on Island 5 in the water labyrinth on the small island with two people

Mantine - I dont think its available in FR/LG..you have to import from Colusseum

Remoraid - trade over from ruby or saphire

Tyranitar - catch a larvatar on island 7 and it evolves at lvl 45