La → Lu
Most lanthanides commonly form +3 ions and have similar ionic sizes. That is why ores often contain several of them together and why separating them on an industrial scale can be difficult.
Neodymium and dysprosium are important in powerful permanent magnets. Europium and terbium contribute to luminescent materials. Cerium is used in catalysts and polishing materials, among other applications.
Despite the name 'rare earths', many are not especially rare in the crust. The real challenge is often finding concentrated deposits and separating elements whose chemistry is strikingly similar.