The one rule of lifegain: sources feed payoffs A lifegain deck has two halves, and it is dead without both: Sources cards that gain you life, ideally incrementally and repeatedly (lifelink, whenever a creature enters triggers, upkeep gainers)
They can have just a singular color in the casting cost and then the other three colors inside the text box, similar to what they did with General Tazri, whos technically a white legend but whose color identity includes all five colors so you could build a five-color Ally Commander deck with General Tazri as your commander
However, if you wanted a resource to explain why characters may have different skin colours in different adaptations, or some simple examples that disprove certain arguments, then Ive got you covered
Blue Threshold Cards Ranked Blue was really good at putting cards in the graveyard and abusing that at the time
I like this Loki card a lot because it encourages aggressive play but is also a bit of a card draw engine and still works well as a control Commander, too
Hurricane , Whirwind , Squall Line , and Windstorm either kill all flying creatures outright or deals enough damage to put them down