Grass, Flying and Rock types.
Rock, electric and ice.
fighting, fire, and rock.
Use ice or fire type pokemon
Use ice type Pokemon or have a Pokemon that knows Ice Beam.
A fighting type, a ghost type, a rock type, a ice type, a water type.
The following are good against ice type Pokemon... Fire Grass Ice
A Fire-type Pokemon can deal 2x the damage to Grass, Ice, Bug, and Steel-type Pokemon.
By using Fire, Ice or Flying type moves.
Well the last gym leader is a dragon type leader so you need an ice type pokemon and/or dragon type pokemon. Idk what his name is but a guy gives you a level 15 Datrini and it is a dragon type pokemon. For an ice type pokemon, go back to the cave (idk the name of the cave but it is a ice cave) and get an ice type pokemon like swinub and raise him and beat Blair!
Ice type Pokemon can easily defeat lance's Pokemon also for his gyrados and aerodactyl you can use an electric type.
Rock type Pokemon are strong against flying, ice, bug and fire type Pokemon.
The best way to beat her ice type Pokemon is to use fire type Pokemon. Also Ice type Pokemon don't like steel, rock and fighting types.