Mana sources that can become fresh cards later in the game are really good, especially in a format like Commander with such long games
The codes can be used on any order from Pokemon Center, so if you're looking to pickup something for a holiday gift, get yourself some promo cards to go along with it.
And, if youre really hurting to make it into a Control Magic, just come ready with two or three other ways to gain small amounts of energy
You can obtain the Cynthia (2-Stars rarity) card by opening Space-Time Smackdown: Palkia from Space-Time Smackdown set
As card #165 in a set with 156 printed cards, it sits in the secret-rare numbering pulled less often than anything in the regular checklist
Some opinions and questions have been addressed via the aforementioned articles and posts, but to reach a larger audience I feel a lot of the information, and the expansion of that information to make it clearer, bears repeating