Another good place for Speed EVs is Pidgeotto Hordes in Five Island Meadow, Kanto 100% encounter rate.
Another good place for Attack EVs is Nidorino Hordes is Route 15, Kanto 100% encounter rate. It's not close to the PC but it's relatively easy to access if you use fly.
It would be wise to remove this as I don't think you can find Pelipper's there anymore. Only Mantine's. If I'm wrong, feel free to ignore this.