While these normally don't hold much value, having a decent number of them will help players fill out their decks quickly until they can collect the cards they really want
Make a billion tokens, make a billion mana, draw a billion cards, pump all your creatures, and swing for lethal in a single turn, is what Tomer said that usually happens with this commander if its let free
For set checklists and card numbers, Pokellector is a common reference
The binder was organized by team, and he was eager to show off the section dedicated to his favorite one: the Philadelphia Eagles
My personal favorite was Malignant Growth, a much maligned Blue/Green Enchantment that was interesting, to say the least, especially in melee games