Like everyone else in his family, Elio adores the color "Silver" - representing Wolfgang, who's the pride of his family as it's current patriarch, in addition to being the notable source of their family's surname [Argentium].

Outside of this, Elio also loves the color "Black" for various reasons:

1.) His physical appeal being somehow heightened whenever he's clad in black - making it a complimentary color.

2.) The Nigredo Pokemon under his possession - fitting his shiny aesthetic via being a stark reminder of certain black gemstones bearing unique patterns - only noticeable yet somehow more beautiful due to the primary color acting as a backdrop.

3.) His personal relationship with and slight adoration of Zekrom - and by extension, Black!Kyurem, deeply enamored with its unique black palette (which emphasized the other colors decorating its physiology) and production of Black Lightning.