Technology-critical elements (TCEs) are elements for which a striking acceleration in usage has emerged, relative to past consumption, and which are critical to emerging technologies.
Wikipedia provides a useful list:
Rare-earth elements (REEs)
In atomic order:
Light (LREEs)
- scandium
- yttrium
- lanthanum
- cerium
- praseodymium
- neodymium
- promethium
Heavy (HREEs)
- samarium
- europium
- gadolinium
- terbium
- dysprosium
- holmium
- erbium
- thulium
- ytterbium
- lutetium
Platinum-group metals (PGMs)
- iridium
- osmium
- palladium
- platinum
- rhodium
- ruthenium
Other elements
- antimony
- beryllium
- caesium
- cobalt
- gallium
- germanium
- indium
- lithium
- niobium
- tantalum
- tellurium
- tungsten