UICardExplorer
The Card Explorer allows you to browse through all the cards at any time you wish. No changes to a deck can be made here, use the Deck Editor for that.
A. These are various filters which can be used to restrict the cards displayed. Sort results by clicking on a column heading.
B. Card stats.
C. A greyed out entry represents a card which has yet to be implemented (it is categorized in the Status filter as "Missing").
D. A playable card that is fully supported by Magarena.
E. Community rating from 0.0 (useless) to 5.0 (awesome) as sourced from the Gatherer website. Missing cards have a default rating of 2.5.
F. Opens the Card Script viewer which lets you examine the underlying script and groovy files behind the selected card.
You can also double click the table row to do the same thing.