Well some people have came up with good ideas, some have been idiots e.g:
degeneration x: I don't wanna fill the pokedex, that's boring
some random dummy: I got one, why don't you fill the pokedex, that'd be UBER FUN! <----- DUMMY ALERT!
Well TBH FR/LG aren't very fun IMO, I only got it in the first place to help fill me dex on sapphire (aah back when sapphire was my main game, sweet memories!) and get a charizard for my team. I play emerald now and that has the most rewarding in-game experience of all the gb games so far, the battle frontier and secret bases. But for FR/LG ummm, pick a pokemon that has a type advantage over one in your team and use that instead, I'll show you an example:
Let's say this is your team:
Blastoise
Butterfree
Tauros
Raikou
Gengar
Flareon
Now the type advantage part:
Blastoise <--- Victreebell (Not sure on the spelling of that lol)
Butterfree <--- Fearow
Tauros <--- Hitmonchan/Hitmonlee
Raikou <--- Dugtrio
Gengar <--- Hypno
Flareon <--- Golem
And then beat the E4 and everyone who wants a re-match with that team (not the example of course lol.)