The Rarity of a card represents how frequently it was distributed in booster packs and other means. This official rarity is printed in the Collector's Info in the lower-right hand corner, and is usually represented by a single letter, though other combinations are possible. Like in most trading card games, not all cards in the same rarity class are created equal, so determining a card's worth is more difficult than merely looking at the printed rarity.

A summary of each rarity and what it means is given below.

First, a word on how most cards were distributed (as this was the primary means of manipulating a card's rarity). Cards had two primary means of distribution for most of the game's run: booster packs and starter boxes.

Starter packs, 2 per set, were specifically designed for new players and came with a specially-designed deck centered around a particular companion. That companion was marked with a special rarity, Premium (P) and always included two copies per box (in The Fellowship of the Ring, those two Premiums were Gandalf, The Grey Wizard, and Aragorn, King in Exile). The other cards included varied, but were always the same for a particular box, except for 3 random Rare (R) cards to mix things up.

For Shadows and Black Rider, all non-rare cards included in the Starter Packs were given a rarity of S, in an attempt to normalize rarity labels (since Common and Uncommon cards included in a Starter Pack were of course much, much more common than other C/U cards only released through boosters). This was only true for these two sets, however.

Booster packs, on the other hand, were the primary way of getting cards (as it is with most TCG's), and the primary waterline by which rarity was judged. Each booster pack contained 11 cards, made up of 7 Common (C), 3 Uncommon (U), and 1 Rare (R) card. There were the same number of each rarity in each set; base sets like Fellowship had 121 of each, while expansions had 40. This meant that, if you were to collect a complete collection of 121 rares from a base set entirely from booster backs, you would have about 363 uncommon cards, and 847 common cards. This assumes you never got any duplicate rares, and if you wanted a complete playset (4 of each card, which is the maximum you can have in a particular deck), your Common/Uncommon set would quickly approach quintuple-digits–and that's just for one set!

In addition, each booster pack had about a 1/6 chance of having one of the cards randomly replaced with a full-foil card of a random rarity. This meant that collecting full foil sets was significantly more unpredictable, and also could result in some interesting booster packs: for instance, this could result in a booster with two rares (one of them foil, replacing one of the common or uncommon cards), or a booster with no rares (if the regular rare card was replaced with a foil common or uncommon). Due to the mechanics of inserting foils into early sets, it was possible - though very unusual - to open a pack with more than one foil card plus an ordinary rare.

So, in summary, Common (C), Uncommon (U), Rare (R), and Premium (P) were the “standard” rarities that the vast majority of cards in the game were granted.

Promotional cards were given out to promote up-and-coming sets and were usually alternate-image versions of previously existing cards. For instance, Faramir, Son of Denethor (P), was packaged with Collector's Editions of The Two Towers movie. Promotional cards were almost always exact duplicates of other cards (except for the card image itself), and so were considered the same from a game judgement standard. There are several important exceptions, however, including 0P56 through 0P60 and 0P62 through 0P67. Most promotional cards have a P rarity, but towards the end of the game's lifespan a few promotional cards with D rarity were printed and handed out.

This meant that for players who focused on the game, Promotional cards were not particularly worth the effort getting, whereas for collectors it was practically a whole new set to collect. This was enshrined by the fact that all Promotional cards are part of set 0, and this is the only way to differentiate a Premium card from a Promotional card. The effective rarity of Promotional cards varied wildly; some were tournament prizes, some packaged with other products, some printed and distributed as much as any Premium card. The most hard-to-find card is generally considered to be 0P127, Aragorn, Defender of Rohan; one copy sold for US$499.

Decipher also printed several oversized cards; these cards were given a rarity of M (and were of course not tournament-legal).

Rare Plus (R+) was a rarity unique to the Reflections set, which was released between Siege of Gondor and Mount Doom. Half of the all-foil 52-card set were Rare, while the other half were Rare Plus. These were distributed in 18-card booster packs composed of 2 random rares from Reflections and 16 random cards from all previous sets (this was a way for Decipher to dump some of their overstock). About once every two-and-a-half packs, a card would be replaced with one of the Rare Plus cards, in a manner similar to foil cards, and thus the name: not quite a rare, not quite a foil (though all Reflections cards were foil).

Starting with the Shadows set, alternate versions of select cards were reprinted as the “Legends” series meant to represent particularly popular cards or concepts. This increased the total number of cards to collect while at the same time making these additions quite rare, as eventually during the set's lifetime these alternate cards would be discontinued. Legends-series cards were always foil, and marked with the RF rarity to differentiate them from their non-Legends counterpart. RF cards were inserted at an approximate rate of 1 every 7 packs, replacing the random rare.

With the release of Black Rider, Legends were joined with the Legends Masterwork series, indicated by a ring O as the rarity. These cards were more than just foil, however; each card used a new card template with a completely redone color scheme and sometimes a card image that “popped” outside its frame. The visual difference is appropriately striking. The initial set of Legends Masterworks in Black Rider had an * for a rarity symbol (see Legolas, Of the Grey Company (O)), but this was changed to an O in sets 15 on. Legends Masterworks were inserted at an approximate rate of 1 every 36 packs (i.e one per booster box).

Tournament Foil cards were distributed during the Shadows block as rewards for winning official tournaments, or in some cases as a reward for purchasing a certain amount of product (earlier, tournament winners received random foils.) There were 9 in total; all were foiled versions of cards from Black Rider and Bloodlines. These cards are unique in that they were not distributed by Decipher, but by their partners in France, Germany, and Italy, and so were printed and handled entirely overseas. As might be imagined, these are among the rarest of cards due to the separation of markets.

See this thread for more information.

There are a number of cards within the database for set 0 that were never actually printed. Some of these, such as Faramir, Captain of Ithilien (AFD), Goblet of the White City (SPD), Green Dragon Mug (SPD), and Rohirrim Stein (SPD), were jokes released on Decipher's website for April Fool's Day and Saint Patrick's Day, respectively.

There were also a number of cards made exclusively for the LotR-O system that may as well have been joke cards. Versions given as tournament rewards were given rarity D (a letter also used for printed promotional cards in 2005-2007), and cards that were a part of the ”Triumph and Menace” mini-set were given a rarity of W (a rarity generally used for other virtual cards as well, but are not represented here in the wiki).