We have a love/hate relationship with lands
Whenever Kain deals combat damage to a player, that player gains control of Kain
The only time I have ever seen this being used is for enchantment recursion but it does have the potential for some more creativity
All of Them I could quibble over Signets, Talismans, Fellwar Stone, Mind Stone, and so on, but truth is all the 2-mana rocks basically play out the same regardless of extra utility
It's a temporary creature for sure, but sticks around for long enough and meaningfully buffs your board several times
You can get so much value out of recurring creatures in Commander, so this is a great option for decks that want to see creatures hit the graveyard or those looking to reuse enters-the-battlefield (ETB) abilities after creatures have died