From Google Trends Frequency of searching pokemon card(s) over time
Reshiram is effective itself against Pokmon with Safeguard , and it can help you keep up the Prize tradeoff when facing non- EX decks
Its completely fine to ask what the card would go for raw and ungraded, and to walk away if the pricing doesnt make sense for what you need
702.187b: Mayhem [cost] means As long as you discarded this card this turn, you may cast it from your graveyard by paying [cost] rather than paying its mana cost. Casting a spell using its mayhem ability follows the rules for paying alternative costs in rules 601.2b and 601.2fh
It was also confirmed that no cards will be banned for at least the rest of 2025, bar any Nadu-type situations where a card becomes "generally reviled" and requires a banning
Allow me to remind you that we denote an ability on the stack, a card, a copy of a card or ability, a spell, a permanent and an emblem as objects