I would argue that Daeron's Runes should be a three-of in every deck that has a Lore hero. Conventional card game wisdom goes that you should build the smallest deck possible, so as to get your most important cards early and often. Three copies of this free, instant draw effect - for most purposes - reduces your minimum deck size to 47, with the barely-existent drawback of having to discard something afterwards. You'll almost never have a full hand of things you immediately need or can't replace, and you'll often want to dig for a specific card that you need more than what you currently have. You'll also probably have extra uniques to toss at some point, or cards that you can interact with in the discard pile later.
Daeron's Runes
Action: Draw 2 cards. Then, discard 1 card from your hand.
Gandalf, The Fellowship of the Ring
Foundations of Stone #108. Lore.
I find it weird that this card has only one review, so i decided to make sure that everyone know this is the second best card in the game, after steward of gondor. If you're running lore, you need to run this, 3x. It makes you go through deck way faster, and the selected discard means you can ditch the least useful (or useless) card at the moment and keep going. It's a card that makes foundations of stone a good expansion to purchase multiple copies of.
This is literally the most broken card in the entire game. And I mean design-fail level flawed one. It just must be auto-include in any deck able to cast it (having hero with a lore resource icon, or Song of Wisdom). The card costs nothing. It replaces itself, filters a player deck and you can even play it when you draw it and quest prevents you from getting any resources (I mean no rebuy, just zero cost). Imagine you have two combo piecies in your deck and no limit for a number of copies in a deck. Would you be better running 25 card A and 25 card be? Or one copy of card A, one copy of card B, and 48 copies of this madness? You could draw 15 cards A in a row and never assemble the combo. Similarly, you must have noticed how Surge keyword is anoying. Imagine simple treachery card: "The first player chooses a character. Deal 1 damage to that character. Surge." Well, encounter deck consisting only of copies of such card would make you lose on the spot! In Magic the Gathering, this would be the best card printed ever, like 500% than Black Lotus. I don't get how this could ever see print.
Others have already said it, but I'll also say it: with no known exceptions, you must play three copies of this card in every deck that has a Lore hero. I suppose if there was a quest where discarding a card would mean you lose the game or incur some big penalty, then that would be an exception to the rule, but I'm not aware of any such quest.
This is a great card draw tool, as mentioned below, I don’t think I have to convince anyone about it. But about the deck-thinning aspect, different from what others said, 3x Daeron's Runes make your deck size effectively 44, not 47. If you imagine you only have 2 cards left in the deck, after you play it you have 0 cards, so two cards less than the nominal number (it doesn't matter that you have to discard one, it's as if it never existed in your deck). In terms of card draw, you end up having the same hand size, but you see two new cards; often you have duplicates or cards you are not particularly interested in (or which you give less value to what you could potentially draw), so in many cases you thin your deck by one card (replacing Daeron's Runes) and get a new, potentially interesting card (thinning your deck by one more). A 0-cost card that does card draw and deck thinning this way must be one of the most powerful cards of this type.
While this is an excellent card and should be included in most Lore decks, I disagree with those who say it has no drawbacks and should be included in every single lore deck. Some decks needs to have a high number of allies for certain cards to hit consistently (ie A Very Good Tale) and another example is Zigil Miner decks, where you may want most cards to cost the same amount. While these drawbacks will still rarely outweigh how good this card is, they are still worth consideration.