"Rare" and "valuable" aren't the same thing. Here's how to read a card and tell what you've actually got.
1. Check the rarity symbol
Bottom of the card: a circle (common), diamond (uncommon), or star (rare). Modern sets add tiers above that — double rare (ex), illustration rare, special illustration rare (SIR), and hyper/gold rare. The higher the tier, the scarcer.
2. Read the set number
A number above the set total (e.g. 201/197) is a "secret rare" — pulled beyond the base set, usually the chase cards. Those are where the value concentrates.
3. Look for the art style
Full-art and "alt-art"/illustration rares — where the character spills outside the normal frame — are the most demanded modern cards. The special-illustration rares (SIRs) are typically a set's most valuable pulls.
4. Confirm value with sold comps
Rarity ≠ price. Check what the exact card actually sells for before assuming it's worth money:
If it's worth grading, run the math with the grading calculator first.