I’m doing a catchless hardcore nuzlocke, and I’m trying to make a plan. Glaceon and Leafeon are not in this since there isn’t a mossy or icy rock in the game and and I don’t want to use Flareon, since you can get a macargo, jolteon since you can get amphaross or vapoureon because of quagsire. So do I use umbreon or espeon?
Honestly, if I was you here I'd go for Umbreon. You can get the TM for Taunt early on, if you haven't already. Would be better bulk then Quagsire because Quag just gets destroyed by a single grass type.
Plus, it'll be immune to Sabrina's team when you reach Kanto.