Like most Pokmon cards, the value of Larvitar depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (HSUnleashed)
With The First Chapter, Rise of the Floodborn, Into the Inklands, and Ursula's Return out of the picture, several cards that were staples in the game that didn't receive a reprint are no longer viable unless you're playing in the Infinity format
If youre curious about how popular a pack is when it comes to sales, you can use sites like TCGPlayer to monitor trends
Ive mentioned on E4 before that my favourite card from Champions Path is Swablu: The artwork is so simple yet it has so much to offer: a stream, a meadow, a tree, a rainbow - a way of painting a picture in my imagination of where in the real world this may be
It is also possible to filter by expansion (set) by typing "e:SET_ID" in the search bar