The most valuable card illustrated by Kouki Saitou is Charizard (Skyridge) at $3,000, ahead of Charizard δ ($1,200) and Rayquaza ($800).
Value counts each card once at its highest-priced printing. The homepage leaderboard additionally requires a priced rarity cohort, so its totals run slightly leaner.
By TCGplayer market price, the most valuable Kouki Saitou card is Charizard (Skyridge) at $3,000, followed by Charizard δ (Crystal Guardians) $1,200, Rayquaza (Emerald) $800, Arceus & Dialga & Palkia GX (Cosmic Eclipse) $566, Lugia (Unseen Forces) $400. Prices are TCGplayer market for raw copies (any condition) and refresh daily.
TickerMint tracks 661 Pokemon cards illustrated by Kouki Saitou across 670 printings, with a combined market value of $21,120 counting each card once at its priciest printing.