Ice Age as a term can refer to a few things:
- A time when the 1/3 of the Earth was covered in a constant winter, hence an Ice Age. The fact that 1/2 of the ground was covered in deserts does not lead to it being called Desert Age mostly because those lands weren't Europe or North America, and thus are irrelevant (fun fact: we're technically still in that Ice Age, it's just that all of human history has taken place during what's called an "Interglacial;" things will freeze over again in a couple thousand years regardless of how much pollution America's Oil Companies Shit out).
- A series of mediocre movies by Blue Sky Studios (a bunch of Dreamworks wannabes working for Fox) about a bunch of prehistoric creatures going on adventures. Probably the best thing the company has done, which isn't saying much.
- A two player board game where you control a bunch of humans trying to kill all the mastodons, not for food but for good old extinction. Fun fun fun.
Though most often when /tg/ uses it, it's to refer to the Magic: The Gathering block and first set in it, detailing the Ice Age caused by this dumbass after he unleashed the Golgothian Sylex to ultra-kill his Phyrexian-possessed brother, both their armies and "win" the Brothers' War. At the end of the first set the Planeswalker Freyalise casted the World Spell to thaw Dominaria, which looked like a good idea but ultimately caused bad shit to happen so people had to form Alliances (the second set) to defend themselves. Finally, ten YEARS after the release of the set (and a retcon of the spectacularly shitty Homelands as the third set in the block) they released Coldsnap, which details what exactly happened during the end of the Ice Age.
Ice Age is known for adding a couple of new mechanics but the most famous one is that of Snow Lands: Lands who give both regular mana and snow mana, which was required for certain spells and abilities. It is also the only full set/block so far that has had major Viking themes in its art and flavor, which is absolutely perplexing when you consider what the rest of fantasy is like. Also famous for being an all-around terrible set, though not as horrible as the notorious Homelands expansion. Its redeeming qualities are the introduction of the so-called "pain" lands (that offer two types of colored mana but at a cost of 1 hp on top of colorless mana) like Karplusan Forest, which were and still are widely used. And, of course, one of the if not the most bonkers black card ever - Necropotence. 
|Settings of Magic: The Gathering|
|Pre-revisionist:||First Magic Sets - First Urza Block - Arabian Nights |
Legends - Homelands - Ice Age - Mirage
|Weatherlight Saga:||Portal Starter Sets - Second Urza Block |
Tempest Block - Masques Block - Invasion Block
|Post-Weatherlight:||Otaria Block - Mirrodin - Kamigawa - Ravnica - Time Spiral|
|After the Mending:||Lorwyn - Alara - Zendikar - New Phyrexia |
Innistrad - Return to Ravnica - Theros - Tarkir - Eldraine - Ikoria
|Two-Block Paradigm:||Kaladesh - Amonkhet - Ixalan|
|Post Two-Block Paradigm:||Eldraine - Ikoria - Kaldheim - Strixhaven|
|Never in a standard set:||Fiora (Where the Conspiracy sets take place) - Kylem (Battlebond)|
A functional reprint of a green staple card. Since it has a different name, you can have 4 of both in your deck.
Illusions of Grandeur
Part of the famous Trix combo when paired with Donate
Massive draw engine.
Great for wiping the board of weak creatures.
It's mana acceleration and a wall in common.