Its FireRed, you cant catch a Magmar without tradingThe most recent team I used was -
Blastoise
Nidoqueen
Jolteon
Dragonair
Nidoking
Exeggutor
Aerodactyl
Rapidash
Pikachu
--- These are the main Pokemon I was rotating with throughout my journey..
But in general I would advise Blastoise, Dragonite, Nidoqueen/king, Magmar, Aerodactyl, Lapras - there's so much to use in this game, just pick something that works synergetically :]
Ninetales is in LeafgreenThere's no "best" team. Personally, I plan on using Venusaur, Starmie (or in your case, since you're using FireRed, Cloyster), Ninetales (which you can swap for Arcanine), Snorlax, Dragonite, and Dodrio.