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The other reason for the complaints is that as mentioned above, unlikely things are still possible

Cycling a card costs one mana these days, and that's all you need to trigger Astral Slide

When Ranger of Eos enters the battlefield, you may search your library for up to two creature cards with converted mana cost 1 or less, reveal them, and put them into your hand

Second, because they can make any mana colour they can be great for getting cards on the board that you just dont have the lands to support, meaning a deck built around them doesnt need to worry if a card outside of its main colours is useful to have

On the topic of Llanowar Greenwidow from Dominaria United , its the latter

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