I went into this topic in some detail in my first article, but the comments to that article highlighted several other approaches that deserve to be mentioned
Can you sell it and buy yourself a house as a result
In order to evolve your Pokmon, give them Stardust and Candy
Besides Pikachu, it is the franchises most recognizable Pokemon, and since the beginning has been synonymous with value and rarity in the Pokemon TCG world
Morgul-Knife (Shadowspear) Exxaxl: Shadowspear was one of the cards I first noticed becoming expensive because of Commander
If you dump Creakwood Liege, Boartusk Liege, Wilt-Leaf Liege, Thistledown Liege, Mindwrack Liege, and Glen Elendra Liege into that Kinnan deck as six extra anthems with good stuff on the side, I'm going to be questioning it