I like flareon
there is only torkal that is the only fire type right in emerald i think.
Because Torchic, Combusken, Blaziken, Numel, Camerupt, Slugma, and Magcargo never existed. D: There's probably more, though.
Which Eeveelution to evolve it into is totally dependent on the members of your team, the IVs, and the Nature of your Pokemon. Until you give us that information, we can't really give you a good answer. However, I can tell you that Flareon is seldomly used, and Umbreon isn't very useful at times. Espeon is outclassed by numerous other special sweepers like Alakazam and Gengar. That's the main reason why it isn't used anymore. Your main choices are between Vaporeon and Jolteon. Vaporeon is arguably the most useful out of all three of them. It's incredibly bulky and can pass a Wish to another Pokemon in case you messed up early on. Vaporeon is seen and used by a lot more trainers than Jolteon. Jolteon is okay. It makes a good speedy Baton Passer and a good lead Pokemon, but that's about it. It's small movepool severely limits its sweeping capabilities. Anyways, your best bet is most likely Vaporeon, but then again, we have yet to know the IVs and Nature of the Pokemon, so saying that you would need Vaporeon would be judging by a narrow sense of knowledge. It would be more helpful if you would provide the necessary elements of your Eevee that we need to know to determine which Eeveelution is the best. :3