Thulium is used in color phosphors. Ytterbium is used in color phosphors. Lutetium is used in color phosphors. Hafnium absorbs neutrons and is used to control nuclear reactors. Tantalum doesn't corrode and is used in artificial knee and hip replacements.
Rhenium is rare and is used in special light bulb filiments.
Osmium is very hard and is used in pen points. Iridium is a hard metal which is rare on earth but common in meteorites. It appears in the geological layer near the last dinosaur fossils. This discovery was the first evidence that the extinction of the dinosaurs was caused by a meteor. Platinum doesn't corrode and is used in jewelry.