Here's an idea that's been done already but under a different name:
Barrow-Blade Resource - Major Item 2 marshalling points, 2 corruption points. Unique. Weapon. Hobbit Only. +2 to prowess. Against Nazgul, +7 to prowess (to a maximum of 8) and his body is halved.
Here's a brand new and very powerful ring:
Wraith-Ring Resource - Special Item 3 marshalling points, 2 corruption points. Magic Ring. Playable only with a Gold Ring and after a test indicates a Magic Ring. +3 to prowess (to a maximum of 10), +1 to body (to a maximum of 10), +2 direct influence. Bearer cannot have strikes assigned against him by an opponent. Bearer must make a corruption check modified by -1 at the end of each untap phase if he is not at a haven. If the check fails, an attack is made against his company with 1 strike at prowess equal to the bearer's prowess +6; this attack/strike cannot be cancelled. After the attack, the character is eliminated as normal.
Here's a card that's now been done in Dragons (I think):
Farmer Maggot Resource - Ally, 4 mind, 1 marshalling point 2/8, Unique. Playable at Bree. Tap to cancel one attack of prowess 7 or less. (It needs a quote about his dogs since that's how he cancels the attack, but I can't find my copy of The Fellowship of the Ring)
And here's one from Isildur:
Rope Resource - Minor Item 1 corruption point, 0 marshalling points. Scout/Ranger only, and only when moving to a site in a dark-domain. Tap rope to lower the hazard limit by one (to a minimum of two).
Here's an EXTREMELY long card text with lots of concepts etc. within it:
Rally Forces Resource: Short Event Diplomat only, Warrior only during the organization phase at a site where a faction you control has been played. Diplomat makes an influence check modified by -2 against the faction. If successful, the Warrior makes a corruption check modified by -2. If successful, the faction becomes an ally (still considered a faction) under the Warrior's control until end of turn, when it is discarded. Its prowess/body is 6/- (it may not become wounded or eliminated). It may face multiple strikes in an attack, but no more than the number of marshalling points +2 in a turn. It may not tap; tapping effects are ignored. Cannot be duplicated on a given faction. Alternatively, may cancel a Siege at a site where a faction you control has been played; the faction is discarded.
Here's the only exact card name I got two of:
Grima Wormtongue Hazard - Permanent-Event Unique. Corruption. 4 corruption points if played on a man. Bearer makes a corruption check whenever he faces a strike. If at a site where information is playable you may discard Grima Wormtongue and tap the site.
Grima Wormtongue Hazard - Permanent-Event Target character loses 2 prowess and 2 body + all direct influence. A Wizard at the same site may tap to attempt to remove the Wormtongue. Make a roll or draw: if the roll is greater than 5 Grima is removed from play.
Here's a card that specifically causes trouble for Hobbits, though not much:
Fresh Mushrooms Hazard - Short-event Tap a Hobbit of the attacker's choice until the end of the turn. May not be played as part of a combat resolution sequence.
Here's a very cool idea, to which I'd add that Rescue Prisoners can be played on this to free all currently held prisoners:
Prisoner Resource- Permanent event 5 marshalling pts. Play to cancel one attack. Opponent choses one of your characters in the company to be taken prisoner. He may only chose a wizard if he is the only character in the company. Put the prisoner aside with all his items. You may then rescue the prissoner at a Dark-hold by first facing any automatic attacks and then facing an Orc attack of three srtikes at 8 in prowess. You may then return the character and all his item to the rescuing company. You may do this at an already tapped site.
Here's two both by one person, including a Silmarillion one:
Feanor Character - Warrior/Sage Elf Home Site: Grey Havens Unique. No member of Feanors company may posess any one of the 3 Silmarils. +3 to all corruption checks. +3 direct influence that is usable only against Galadriel.
Staff of Saruman Resource - Greater Item +? body +? prowess ? corruption Unique. Only usable by a Dunedain, Elf, or Wizard. Adds Diplomat skill to non-Wizard bearer. For Wizard bearer adds missing skill.
Another Animal helper:
Animal Intelligence Short or Long Event Choose the defenders of Wolf, Spider or Animal attacks played this turn.
and another Nazgul helper:
Nazgul Drake Hazard - Creature, Playable at Dd, Dh, Sl, Sh Two strikes. Attacker chooses defending characters. A Nazgul played after this card may be keyed to the same site or site path and his prowess is modified by +2 but his body is modified by -3 if the Nazgul Drake is defeated. 3? marshalling points.
And here's another Palantir:
Palantir of Eressea Special Item, 5? corruption Playable with Favor of the Valar at the Grey Havens. Unique. Palantir. Bearer may tap to use the ability of any Palantir. Alternatively, if bearer is a Wizard, he may tap to automatically win any influence check. Additionally, your wizard may tap to use the ability of any other wizard. If you choose to use this ability he may not duplicated his own abilities.
And here's a nice one from Shadowfax:
A Long Expected Party Resource - Permanent-Event Unique. Playable during your site phase if a Hobbit is at a haven of yours. On the third turn this card is in play, and if you have all of your characters at Bad End with Bilbo present, gain 10 General Influence. If all of your characters are not at Bag End by the end of your third turn, discard this card. If Doors of Night is ever in play, the hazard limit for all of your companies is increased by 2. If Gates of Morning is in play, the prowess of all Creatures keyed to your characters is reduced by 2. Discard if Bilbo is slain.
And here's yet another ring, a little like an idea I posted once:
Nazgul Ring Resource - Special Item Playable only after a Nazgul has been wounded or killed. 4 marshalling points, 4 corruption points. Tap ring and bearer to make an influence check against a Nazgul. Nazgul's mind is 2/3 its prowess. Bearer makes a corruption check at -2. If check is successful, the Nazgul becomes an Ally of bearer and is not discarded when its special ability is used.
And another Hobbit who might have been a better choice than old Robin Smallburrow:
Fatty Bolger Character - Scout Hobbit 1/9, If he is not one of the starting characters, he may only be brought into play at his home site. Tap to cancel the effect of any Nazgul hazard keyed to Arthedain, Cardolan, Rhudaur, or The Shire. Fatty makes a corruption check at -6. Home site: Bag End
Here's one from Sauron that sort of sums up the whole game:
The War of the Ring Hazard - Permanent-Event Playable only if Doors of Night and The One Ring are in play. Orcs, Trolls, and Nazgul may be keyed to any region in Gondor. This card is discarded when Return of the King is played.
And here's one from Morgoth even though it's more appropriate to his servant:
Sauron Hazard - Creature 26/12, May only be played keyed to Barad-Dur, unless Doors of Night is in play, in which case it may be keyed to Mount Doom. Before this creature is fought, each character in the party must make a corruption check at -5. If Sauron is defeated, then the player defeating him wins the game! Sauron may be played as a resource short event by any company which ends its turn at Barad-Dur.
And an idea from Beorn:
Wandering Nazgul Hazard - Short-event A Nazgul may be played as a hazard-creature against a company moving in a free-domain, border-domain, or wilderness. The Nazgul's prowess is halved. Alternatively, if Doors of Night is in play, the Nazgul gains an additional strike.
And another thing from Isildur with a few suggestions on how to make Silmarillion cards work as well as two different ideas:
The idea of a Silmarillion expansion has been tossed around, but most people said it would be entirely too powerful. One way to put in the powerful cards (like the Valar) would be to make them amazingly expensive to use. However, any Magic player will tell you that ways will be found to circumvent the high costs, so that's probably not a good idea. The other way is to make the cards that would be very powerful (like the Valar) not characters, but permanent-events that are mutually beneficial. For instance: Morgoth: Hazard Permanent-event. Untaps at the beginning of every player's turn. Any player may tap Morgoth to add 5 to the prowess of one attack or add 2 corruption points to a character. Ulmo: Resource Permanent-event. Untaps at the beginning of every player's turn. Any player may tap Ulmo to cancel an attack keyed to costal seas.
Finally, here's my own ideas that have been in COTDS (I have many more, I may post them eventually):
Sauron Hazard - Character (!) 6/9, 15 mind, 20 direct influence Unique. Any cards requiring Doors of Night in play may substitute Sauron instead. Home Site: Any dark-domain
Manwe (he's the king of the Valar, in case you haven't read The Silmarillion) Resource - Ranger/Sage/Diplomat Ally, ultra-rare 8/*, 20 mind, 8 marshalling pts. * = cannot be killed by any means while a resource (well, he is a god, after all) Unique. Playable at any haven, free-domain or free-hold. Tap to cancel one strike from a hazard creature attack; Manwe's controlling character must make a corruption check modified by -4. You may also discard Manwe for 12 more marshalling points; he then becomes a 30/12 hazard creature with 8 strikes which immediately attacks your company. If influenced by opponent, this effect changes to 8 marshalling points and the attack is reduced to 1 strike.
Helpful Danger Resource - Short-Event Spell. Wizard only. Playable at any time; you must tap your Wizard when you play it. This card allows you to play one Hazard as a Resource on yourself.
Dangerous Help Hazard - Short-Event Playable only if your Wizard is revealed. Your wizard must tap when you play it. Allows you to play one resource Short-, Long-, or Permanent-Event from your hand as a hazard on your opponent. Both it and this card count towards the hazard limit. Your Wizard must make a corruption check modified by -2.
Hope you found this interesting. Thanks a lot to everyone who sent in an idea. Also thanks as I always say at major issues to all the people who help make this possible, the raters, ICE, everyone who sends in comments, etc.