I bought Fire Emblem: Awakening way back when it came out, yet have never played it. The thing is, with the 3DS eShop closing next month, I thought I should look into getting some of the DLC in case I do ever play it. What is best DLC for Awakening to get?
Make sure to boot the game and connect to SpotPass at least once before they shut it off. That will ensure that you're able to access six optional endgame characters that are technically part of the base game.
"The Future Past" DLC is a better ending than the game's actual ending and is my top recommendation..
The "Scramble" pack includes three levels which have support-like conversations between units which cannot support each other. An excellent choice if you like the cast.
The "Golden" pack offers opportunities for convenient grinding, which, I dunno, you might want.
"Lost Bloodlines 2" and "Smash Brethren 2" provide access to two DLC-exclusive classes.
Additionally, for completionists, there are some DLC-exclusive skills available from "Champions of Yore 3," "Lost Bloodines 3," "Smash Brethren 3," and "Rogues and Redeemers 3;" only that last one is really notable, though, as it's a skill that increases stat caps, allowing you to make a unit stay reliably ahead of even the hardest enemies on the highest difficulty.
"Apotheosis" was designed to be the hardest level in the game, but it has been proven beatable without any other DLC or even any particularly optimized team planning.
They were really just throwing shit at the wall and seeing what sticks. Nowadays they'd just throw all of that into a single season pass and charge half the total price for it.