The Burning Crusade (lv 70)

Tempest Keep lv70 25m (4/4) - Fairly difficult instance to solo as a feral. The gold might be worth something, 250g ea boss and 300g for Kael'thas. The trash packs, if looted, gives about 1 gold each which adds up when killing several packs each reset. Most of the videos show me soloing 3/4 of  Tempest Keep as a lv 80 instead of 85.
Alar (soloed)- This fight is a pretty easy fight which can be easily done in cat form. The video shows how to solo alar @ lv 80. As an 85, your health pool can sustain your cat form with lifebloom stacking and healing touch (via predatory swiftness).

Solarian (soloed)- can be done completely in cat form. Some special ways of avoiding the bomb popping you up into the air is timing skull bash right as you blow up or feral charge back to the boss as you fly up into the air. However, make sure you have 8 yd+ distance in order to satisfy the feral charge requirement. Make sure you dps the priest down asap because their healing done to the boss does add up.

Void Reaver (soloed)- this fight is probably the 2nd most difficult fight to solo as a lv 85. First being Kael'thas of course. The enrage timer is probably not a big problem at lv 85 but I have a personal enrage timer, being inpatient x). Therefore, I dps Void Reaver as cat form but make sure the boss doesn't take my health too low because his constant silence prevents healing spells, faerie fire and demo roar from happening.

Kael'Thas- Solo'd finally... video explains most of it :D
Also, the youtube description will have some helpful macros if you need em.

Coilfang Reservoir: Serpentshrine Cavern lv70 25m (5/6)- 250g ea boss, some nice income but takes a bit of work. The walk back is a pain as well if you die.
Hydross (soloed)- Saving barkskin and survival instinct for when Hydross's stack hits ~50-100% dmg increase is key. The longer you can extend one phase before pulling the boss off the water purification pumps, the better. The adds are easily swiped down but causes you to take a good amount of damage. It also helps to use your predatory swiftness for healing touch and lb stacking when your energy pool is regenerating.

Lurker (soloed)- Very annoying boss that has been bugging out for me during patch 4.1-4.2. However, if he acts normal, you can easily cat form dps down this boss while running around as he casts his water beam ability. Make sure you kill all the adds that spawn and heal up if needed when Lurker goes underwater.

Leothras (soloed)- This fight is very tricky, the Tol Borad resistance trinket might help but isn't necessary for this fight. You must dps in cat form as much as you can during his humanoid form. When he metamorphosis, be sure to stack some hots on yourself and use instant  healing touch on yourself when you can. Save barkskin for several stacks of the fire debuff then survival instinct for very high number of stacks. Bear form and frenzy regeneration if you need to out live the metamorphosis phase. When he hits humanoid again, heal yourself as much you can. The boss will split into both humanoid and metamorphosis form when he hits ~20% health but his RP will allow you to burn his health a lot lower before it becomes very dangerous.

Fathom-lord (soloed)- Very difficult fight but at all cost do not shift out to humanoid form because the boss will nuke you based on your mana pool. Cat form burn the female naga healer and make sure you skull bash any heals she cast. Once the healer is finished off, you can bear form the other 3 npc down.

Tidewalker Lurker (soloed)- Long fight, keep up rake and rip while tanking Tidewalker as bear when your bleeds are up. Try to go cat form and dpsing the adds (murlocs) with swipe.
Lady Vashj- not soloabe because of mechanic

Caverns of Time: Hyjal Summit 25m (5/5)
Rage Winterchill- most challenaging of the 5 because his nova or block combined with his dnd can mean death for you. You want to save stampeding roar and dash for novas that tie in with his dnd and survival instinct and barkskin for iceblock + dnd. What I normally do for this fight and all the other boss fights is have all the npcs aggro to the boss. Extra dps helps, but they tend to die fairly quick to the dnd. Make sure Jaina don't die because I think she resets the instance if she  does? I can be wrong about this statement thou.

Anetheron- pretty easy, tank and spank

Kaz'rogal- pretty easy, tank and spank

Azgalor- pretty easy, tank and spank

Archimonde - simple tank and spank, except for periodic fears and fire patches that you have to watch out for

Black Temple 25m (/9)
High Warlord Naj'entus- Cannot solo
Supremus- fairly easy tank and spank
Shade of Akuma- make sure you clear the whole room, adds that come when the fight engages are easily swiped or single targeted down. Akuma's shade is easy kill once he becomes active.
Teron Gorefiend
Gurtogg Bloodboil
Reliquary of Souls
Mother Shahraz
The Illidari Council
Illidan Stormrage

Sunwell Plateau 25m (0/6) - duo'd all of Sunwell (w/ warlock)
Kalecgos + Sathrovarr (cannot solo)
Alythess + Sacrolash
M'uru/ Entropius

Gruul's Lair 25m (2/2)
High King Maulgar - kill the priest healer while interrupting the heals as much as you can... you will get spammed deathcoil. Bleeds has to kill him basically. Once the priest is dead, you are safe to take it slower as the other gang cannot be healed anymore.

Gruul the Dragonkiller - easy tank and spank

Hellfire Citadel: Magtheridon Lair 25m (1/1)
Magtheridon (soloed)- Even as an 85, this fight is pretty troublesome because if you cannot burst the adds before they heal each other, the damage starts to stack on you. Getting  rake and rip onto two adds and using berserk should assure you a kill. It might be possible to spam swipe them down now because of the increased swipe damage. However, I haven't tried Mags recently due to the gold nerf it received.

Karazhan 10m (11/11)- All these fights are easily dps down in cat form. Although, the nerf to the gold makes soloing this whole instance less worth wild.
Attunmen the Huntsman (soloed)- get a chance at the mount
Hidden place beside Karazhan
Moroes (soloed)
Maiden of Virtue (soloed)
Opera Event (soloed)- if you  get Little Red Riding hood, Run away little girl :)
Nightbane (soloed)
The Curator (soloed)
Terestian Illhoof (soloed)
Shade of Aran (soloed)
Netherspite (soloed)- Soak red beam, Netherspite should die before the next phase of beams. If he doesn't die, soak the green beam. If your dps isn't quick enough, he will gain more health through the red beam which means you won't dps Netherspite down until he phases.
Chess Event (soloed)- Imo, this fight is the most difficult because gear doesn't mean anything. I found moving your 2 pawns in front of King and Queen (warlock) which will allow you to mainly control the warlock and nuke things down. When Medivh uses his cheat ability, fire, move the lock and king a square forward in order to avoid extra damage.
Prince Malchezaar (soloed)