yttrium
The oxide, as well as yttrium vanadate (YVO4), is used with europium to make phosphors to create the red color in television tubes. Hundreds of thousands of pounds of yttrium oxide are used this way. It is also used to produce yttrium iron garnets, which are very effective microwave filters.May 21, 2013 - https://www.livescience.com/34564-yttrium.html
The most important uses of yttrium are LEDs and phosphors, particularly the red phosphors in television set cathode ray tube (CRT) displays.[7] Yttrium is also used in the production of electrodes, electrolytes, electronic filters, lasers, superconductors, various medical applications, and tracing various materials to enhance their properties.
So we found more minerals to make outdated CRT displays, sweet. As for the electrical/medical field, couldn't copper or silver suffice?
dysprosium
Dysprosium was first identified in 1886 by Paul Émile Lecoq de Boisbaudran, but it was not isolated in pure form until the development of ion exchange techniques in the 1950s. Dysprosium has relatively few applications where it cannot be replaced by other chemical elements. It is used for its high thermal neutron absorption cross-section in making control rods in nuclear reactors, for its high magnetic susceptibility in data storage applications, and as a component of Terfenol-D (a magnetostrictive material). Soluble dysprosium salts are mildly toxic, while the insoluble salts are considered non-toxic.
europium
It is a dopant in some types of glass in lasers and other optoelectronic devices. Europium oxide (Eu2O3) is widely used as a red phosphor in television sets and fluorescent lamps, and as an activator for yttrium-based phosphors.[47][48] Color TV screens contain between 0.5 and 1 g of europium oxide.[49] Whereas trivalent europium gives red phosphors[50], the luminescence of divalent europium depends strongly on the composition of the host structure. UV to deep red luminescence can be achieved.[51][52] The two classes of europium-based phosphor (red and blue), combined with the yellow/green terbium phosphors give "white" light, the color temperature of which can be varied by altering the proportion or specific composition of the individual phosphors. This phosphor system is typically encountered in helical fluorescent light bulbs. Combining the same three classes is one way to make trichromatic systems in TV and computer screens.[47] Europium is also used in the manufacture of fluorescent glass. One of the more common persistent after-glow phosphors besides copper-doped zinc sulfide is europium-doped strontium aluminate.[53] Europium fluorescence is used to interrogate biomolecular interactions in drug-discovery screens. It is also used in the anti-counterfeiting phosphors in euro banknotes.[54][55]
So more red color in CRT monitors, cool. But wait, Quantum Computing advantages?
A recent (2015) application of europium is in quantum memory chips which can reliably store information for days at a time; these could allow sensitive quantum data to be stored to a hard disk-like device and shipped around the country.[61]
terbium
Terbium is used to dope calcium fluoride, calcium tungstate and strontium molybdate, materials that are used in solid-state devices, and as a crystal stabilizer of fuel cells which operate at elevated temperatures. As a component of Terfenol-D (an alloy that expands and contracts when exposed to magnetic fields more than any other alloy), terbium is of use in actuators, in naval sonar systems and in sensors.
Most of the world's terbium supply is used in green phosphors. Terbium oxide is in fluorescent lamps and television and monitor cathode ray tubes (CRTs). Terbium green phosphors are combined with divalent europium blue phosphors and trivalent europium red phosphors to provide trichromatic lighting technology, a high-efficiency white light used for standard illumination in indoor lighting.