While a deck like Eldrazi Tron, for example, still uses Leyline of the Void to knock out graveyard decks in the sideboarded games, having access to something that Karn can find in Game 1 gives you the ability to deal with the graveyard in any stage of the match
If you dont have a printer or need to print something bigger, you can go to your local Staples, Costco, etc
Perhaps they'll trigger when you cast spells of that particular colour
I also prefer to play Commander at the highest power level, but the cards mentioned below ought to be considered for pods of all levels too
Most dinosaurs are pretty beefy and have high mana value, so using them without having to pray you untap with them next turn is huge
Obelisk of Urd isn't really exciting when it hits only one creature, but +2/+2 is a sizable bonus, and even a few creatures receiving the bonus is enough for it to matter