All cards in Starter Kits are legal to play in Constructed formats, there arent any silver bordered cards or anything like that
Red and white has access to cheaper creatures with unearth than a lot of other colours, such as Yotian Frontliner, Scrapwork Mutt, Phyrexian Dragon Engine, Reconstructed Thopter, and Scrapwork Cohort
If not, try not to get too attached
Five mana is quite a lot for the effect, but being a colorless card is a huge boon here, and its not as expensive as it could be
Charizard - Holofoil Secret Rare (Pokemon Skyridge) Pokemon Skyridge was one of the final sets produced by Wizards of the Coast, meaning this card only ever saw a single print run
Honorable mentions for Meria, Scholar of Antiquity and Wild Cantor, which while good, require specific types of decks to truly shine