While it is mostly Millennials and Gen Z taking an interest in, and making a buck out of, investing in Pokmon cards, there are also younger people trading cards with an awareness of their financial values
The most important advice I can give is to continue to experiment with all the different keywords until you find a playstyle you enjoy
Mutate was a mechanic introduced in Magic The Gathering's Ikoria: Lair of Behemoths (though it first appeared on a card in the Unsanctioned set)
So for a rough example, there'd be a red legend named "Kandor, the Warrior," but then there'd also be a white legend named "Kandor, the Farmer," and the art would depict the same person, with the idea being that we're representing two different potential paths that his life could have taken
As one of the oldest deckbuilding sites, TappedOut was a household name among playgroups across the world as early on as 2008 (and probably before then)
This one is perhaps my favorite ridiculous bomb finisher that has ever been printed for white