Two Bardic wars means that there are enough instruments to be listed separately. Oddly enough they don't seem to have been used much.
Name: Bass Harp of Truth and Justice
Used by: Daryl
Scarcity: Unique (assumption on my part, but I assume most of Daryl's named instruments are unique)
Power Level: Unknown
Known Properties: Nothing is really known about this except that it has a very deep tone and can sooth the savage X. Then again, that may just have been Daryl's voice.
History: Used once to rescue Liquid-X from the depths of his own torment.
Notable Posts: A Desperate Chance... - It's one use
Notes: One of a multiplicity of one shot instruments used by Daryl. I swear she makes up the name on the spot and then forgets about 'em.

Name: Blue Ocarina
Used by: Link, Excal
Scarcity: Unique
Power Level: Over-Par
Known Properties: This Ocarina is a very good ocarina that allows one to use bardic skills quite well.
History: Originally used by Link, it was handed over to Excal for the duration of the Eternima Saga. During that period of time, Excal used it a grand total of once and then he gave it back to Link and bought his own ocarina.
Notable posts: Welcome to Eternima, Sister Dimention to... - introduction of the Ocarina
Notes: Yet another instrument soon to be forgotten on the board. But at least somewhere, we can be sure Link's playing upon it... (X)At least he's not blowing on the bone flute....

Name: Cello-sized Violin
Used by: Sailor Gaia
Scarcity: Unique
Power Level: Over-Par
Known Properties: Well, yet another weapon that's never really been used. Supposed to be quite powerful, but then again, it IS a bardic weapon...
History: Well, it was going to be used aboard the Whale, but unfortunatly, whil everyone was talking it found it's way into the possession of a certain Treasure Hunter. Ah well, c'est la vie.
Notable Posts: The dang thing was never used, and will never be seen again. Unless Locke ever takes a stab at using the thing and somebody is bored enough to write about it...
Notes: Could possibly have the spike at the bottom of most Cello's which could be used to impale people with making it one of the most lethal bardic weapons ever. (Kudos to Angelicious for the inspiration) (X)Death by a Cello-sized Violin.... Even SYE wouldnt deserve THAT!

Name: Eriol's Keyboard
Used by: Eriol
Scarcity: Unique
Power Level: Average
Known Properties: When the keypad is hit, it makes a sound. Nifty, eh.
History: This keyboard has been in Eriol's possession for as long as we've known about it. The lack of mention this item gets seems sure to keep it there.
Notable Posts: Actually, the thing's never shown up, it's just heavily implied...
Notes: Well, it had to happen eventually. An item that breaks the record and manages to make zero appearances. I'd give it a cookie, but it's just an item, and I ate them all anyways. (X)HEY! Why didnt you save ME a cookie?!?! Greedy spoon......

Name: French Horn
Used by: Excal
Scarcity: Common
Power Level: Sub-Par
Known Properties: It has a low tune, and is somewhat difficult to play.
History: Gotten from the body of the dead messanger bird sent to him by Eidolon X, Excal has had this instrument in his possession ever since. He's used it once, but since then has steered clear of using it.
Notable Posts: Over the Battle - See Excal sit out the exciting battle as he tries to play a rousing tune upon his French Horn *snicker*
Notes: Given Excal's known dislike for this thing, expect him to use it's great weight at some point in the future. (X)Most likely to club an annoying bard. (Oooh, IRONY!)

Name: Harp of Protection
Used by: Excal (Huh?!)
Scarcity: Rare (I'm assuming random instruments brought out by other people are not Unique as they aren't the Bardic Demi-Godess, though the same method does apply)
Power Level: Over-Par
Known Properties: The strains of this harp are perfect for weaving spells of protection.
History: Another one shot instrument, it was used to create a barrier, and will likely remain forgotten...
Notable Posts: Great... - See it in action.
Notes: Y'know, I bet most items are one shot deals, and that's just depressing... (X)In some casses, its a good thing. The last thing we need are constant uses of "The toilet paper of constipation" or the "cookies of tossing" (Krono) Maybe most of the items are key items. After they get used once, they sit around in your BAG unusable, undiscardable, and forgotten.

Name: Lute of Super Summoning
Used by: Daryl
Scarcity: Unique
Power Level: Over-Par
Known Properties: This lute is somehow able to summon any bard, and a few non-bards.
History: Used twice (gasp! shock!) to bring Mario around with some shrooms of growth. Just don't ask about the side effects. (X) and dont smoke em either.....
Notable Posts: You will NEVER defeat me! - uses it to de-chibify herself
Notes: Y'know, I wouldn't be surprised if X is dating Daryl partially to get his hands on this thing so he can summon Shiva, Siren, and some cute bardic gals. (X) Shhhhh! Dont tell Daryl.....

Name: Mintaka's Flute
Used by: Mintaka
Scarcity: Unique
Power Level: Average
Known Properties: You blow into it and it makes sounds.
History: It too, has never appeared. Go, alluded instruments go!
Notable Posts: See Eriol's Keyboard, they're mentioned at the same time.
Notes: At least they're cutting away at the percentage of one-shot items... (Krono) Well which would you rather have? A bunch of one shot items, or a bunch of no-shot items?

Name: Muscalibur
Used by: Gildward
Scarcity: Unique
Power Level: Legendary (yeah, I know, it's a bardic weapon. But hey, there has to be one...)
Known Properties: A very powerful harp.
History: Forged in the great Bardic Castle, it lay lost for many years until found by Gildward, gretest of the mortal bards. Since then, it's remained with him except for a scrabble for it after he dropped it while getting blown off the Whale.
Notable Posts: Comic #109, Bard's Tale - see the Muscalibur's original appearance
Notes: Not, just imagine how much trouble Gildward would be in if the stone this thing was in was actually tough (Krono) Well, considering that it was probably placed in the stone by a bard it couldn't be all that difficult to get it out.

Name: Nature's Ocarina
Used by: SRGPI
Scarcity: Unique
Power Level: Over-Par
Known Properties: Plays music
History: Given to SRGPI as a young lad, he's carried it with him as proof of his heritage.
Notable Posts: looms in a tree - I put this here because I felt like it...
Notes: It has prophetic writings on it, though they don't seem to affect the sound.

Name: Ocarina of Dischord
Used by: Valen
Scarcity: Rare
Power Level: Over-Par
Known Properties: A rare instrument of dischord.
History: Made from the wood of the great Baka Tree itself, this Ocarina was given to Valen by Pirotess, a dark fairy. He has sence used it mainly to annoy Daryl.
Notable Posts: Hmmph! - Valen uses the instrument of Dischord
Notes: *Insert witty comment later upon remembering...* (X)Y'know.... I cant help but get the feeling that the Baka fairy has certain.... INTERESTS in Valen..... If you catch my drift.

Name: Titanium Harp
Used by: Daryl
Scarcity: Unique (So far on The Planet anyways)
Power Level: Over-Par
Known Properties: It has mono-moleculer strings that'll slice through almost anything save a bard.
History: Originally belonging to an unknown bard, said bard had the bad fortune of attacking Krono. Krono, having no use for the spoils of that very short battle gave this to Daryl. She's used it ever since.
Notable Posts: A few background details on the harp - I'll let you guess what's there...
Notes: I think this has become Daryl's Primary weapon. (X)If you can call a freakin Harp a weapon. (Krono) It's a weapon alright. Not as conventional as a sword or bow, but it ain't something I'd like to be hit with. And thats not counting whatever skill the bard has.

Name: Twinharp
Used by: Reako
Scarcity: Rare
Power Level: over-Par
Known Properties: Can be used to make another Twinharp elsewhere play the same music
History: Nobody really knows where Reako got it from, but he uses it when he plays bard...
Notable Posts: The first one it appeared in... as always... Not like any of this stuff ever gets used elsewhere...
Notes: Might be a powerful weapon, but we never find out because when the fight starts, Reako pulls out ol' Rival the Grey. (X)Just be glad he pulled out Rival the Grey and not his "Dancing Scimitar"