That volume is a double-edged sword for collectors there are hundreds of distinct Japanese Pikachu cards in circulation, which means knowing which ones actually hold value (and which are $2 bulk) is harder than for any other Pokemon
It all just has to do with demand
While he was fairly useless there, Goyo Guardian is pretty terrifying
For example, in the Sword & Shield sets which were released from 2020-2023 cards featured a similar type-based pattern to the Scarlet & Violet sets, albeit with a striped pattern of chevrons that each contained the Pokemons type symbol
Combine this with Skarmory, Drampa, or even Oricorio, and you have a deck that can take on anything as long as it doesn't brick for extended periods of time
Scavenging Ooze is along similar lines to Deathrite Shaman as a life gain card but is narrower in application and of lower power hence the lower rating on this list