0-1 Land card (Traditional Foil Land replaces a Land in 20% of boosters)
Secret Wonders (2007) Secret Wonders experiments with status effects, disruptive trainers, and energy denial
Most valuable Mega Evolution Pokmon cards Of course, it's always easier and sometimes cheaper to just buy the single chase cards you're seeking
This is not an exact science and is mostly used by PSA for insurance purposes
The color wouldn't be able to deal with anything permanently, but would instead just keep putting off its problems on the theory that it would win before it has to deal with them
Budget 200-1,000 euros: the serious investor 1-2 complete French booster boxes from popular expansions (Mega Evolution, Journey Together) 2-3 Pokemon Center ETBs (exclusive editions) 1 entry-level vintage French PSA card (common or uncommon in high grade) With this budget, you can start building a genuine small diversified portfolio