A 1st edition, holo, shadowless Mewtwo could get you around a grand at a grade 9, and a grade 10 is currently on eBay for $3,000
Duty Beyond Death If you want to save your whole board from ending up in the bin, Duty Beyond Death is a great solution
Each instance of extort triggers independently, so you can pay two for two drains for each spell cast
So its beyond point 6 of PFMs chart with a general 5ish% or whatever annual growth like before the 2020 boom
Why S10B Still Matters in 2026 Three reasons: the set has been out of print since late 2023, Pokemons 30th anniversary in 2026 has renewed demand for Kanto-focused releases (S10B is Kanto-dense Mewtwo, Charizard, Blastoise, Venusaur all get headline spots), and the Japanese version contains two Special Art cards (Mewtwo V SA and Conkeldurr V SA) that simply do not exist in the English PGO release