The Pokemon i always use to beat the elite four are charizard,mewtwo,tyranitar,zapdos,alakazam, and suicune.
Lorelei=charizard for jynx and piloswine, and zapdos' thunder for the rest
Bruno=charizard for onix and steelix, and zapdos with drillpeck with the rest
Agatha=mewtwo or alakazam(you choose) for all of them
Lance=Zapdos for gyarados and aerodactyl,alakazam or mewtwo for the dragonites,
Gary=Zapdos for pidgeot,mewtwofor rydhon,zapdos with alakazam,charizard for execotur,zapdos with blastoise
that's how i usually beat it the first time and the rest of the times
i have beat the elite four 120 times and got my Pokemon to all lvl 100 with 300 hours of gameplay.
hope this helped
use the same Pokemon the second time but beat them for their weaknesses like when you fight Gary the second time, he has a heracross. You can either charizard or zapdos with drillpeck
fighting bug ghost dark rock steel electric dragon ice fire and ground
first you need the rubys in fire red but first beat the elite four
Its best if you have 1 fire Pokemon and 1 ground Pokemon.
The first thing you have to be sure of is that you have beaten the Elite Four. Do that first!
the best fire Pokemon u could have to beat the elite 4 would be blaziken over level 75 or higher
fire
Have a good Fire and/or Ground Type...
fire is Mr mimes weakness
I'd say at least Lv55 if it's your first time.
The Elite Four is in the Indigo Plateau.
fire and ground
Fire, flying, ice, and rock.