At least some of the elements in the diagram are rare earths .such as yttrium and neodymium and europium and lanthanum although the article does not mention these it does mention scandium which is kinda close.
https://www.ga.gov.au/data-pubs/data...nt/rare-earths
The rare earth elements (REE) are a group of 17 metals that comprise the lanthanide series of elements lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu) in addition to scandium (Sc) and yttrium (Y), which show similar physical and chemical properties to the lanthanides. Rare earth elements are a relatively abundant group of elements