While it’s not clear what exactly makes a Dominion card “good” or “powerful,” people do card power level ratings anyway. There are many valid and conflicting reasons to rate a card as good or bad, but some cards are consistently rated as very strong across all of these definitions. Knowing which cards are rated this highly can impact the way you look at kingdoms, as they either have very strong effects or are strong enough to include in a wide variety of decks; knowing what these cards and why there are powerful can be very helpful to you as a player.
So I’ve compiled a list of roughly the top 10% of all Dominion cards and, with some help, written a short blurb on why each of them is rated so highly. Below is a list of those cards, with links to the appropriate articles. If there is a more detailed (and good) resource on that card, the bite-sized article will link to that as well.