Let's say your deck features a lot of cheap creatures with prowess and a lot of tempo-based spells like Force Away and Crippling Chill to help you keep attacking
Abilities that apply "as [this creature] enters the battlefield," including many abilities that ask a creature's controller to choose a color or creature type, are unaffected
Of course, limited is a wholly different animal
Note that some combos are very similar to each other, and so they'll be skipped over in favour of combos that can work in many different colour identities
If you want more written content, make sure to check out our Lorwyn Eclipsed deck techs and be on the lookout for my fun ranking coming soon
Just because a deck can include Characters, Items, and Actions, doesn't mean it has to