Due to the most recent DEC price spike, you might want to grab a few cards, even if all you want to do expand your collection or simply resell it later. Of course, that's all in the Splinterlands Crypto Game.
You should be looking at the most expensive cards of each rarity. This is the best time ever to grab them! We are talking about War Chaang, Mitica Headhunter, Coral Wraith and Soulstorm for Epic. Chain Golem, Cornealus, Kron the Undying, Dragon Jumper and Phantom of the Abyss for Legendary. Khmer Princess, Living Lava, Spark Pixies and Shieldbearer for Rare. Last but not least, Serpentine Spy, Failed Summoner and Albatross for Common.
But why do these cards still hold high prices? That's what you want to ask yourself if you are still wondering whether they are good investments. The fact is, they are real monsters. Their cost-benefit in battle is gigantic. Core cards like these can fit into any team and any battle. It doesn't matter if you are looking at ranked play or competitive tournaments, those cards are staples even when every edition is allowed.
An the other extreme if the spectrum, you also get some pretty solid picks. Thingies almost entirely useless you will never send to battle, but safe purchases regardless because they won't cost you almost nothing more than their base value - at least while the DEC price spike lasts. Not everyday you can purchase newer Gold-foil Epics for measly 10k DEC. But if you look at the market now, Sporcerer will be one of your options. Not bad, considering the whole collection power thing we have now.