Give me a Star and a Gem!

[Phantasmagoriat]

Category - Star - Gem

How, this is gonna work: First, pick a Category. The category can basically be *ANYTHING*:
Artist Album; Artist Song; Genre Artist; Genre Song; Style; Era/Time-period/Country/Location of music etc... you can even make up your own category...
Then, in your best estimation, name one of the more prolific or well-known examples within that category: a "Star"
Then, within that same category, name a lesser-known example that maybe didn't turn out to be as successful,
or seems less-known in comparison to the first one, but you personally really enjoyed: a "Gem"

I'll start off with these:
Supertramp Song - Dreamer - Easy Does It//Sister Moonshine
Supertramp Album - Breakfast In America - Crisis? What Crisis?
Thrash Metal Artist - Metallica - Annihilator
OC Remix - Super Mario Bros Underworld Rock - Super Metroid Anthem of a Metroid Hunter