Compiled data edited in below. Though form and magnitudes could be more specific, everything suggests that this is pretty much complete;
You can have ONE power from each book, total 6 powers, active at any time, though they can be swapped, plus respecs. This list does not try to present them in a specific order.
From Raven Rock Mine: "THE WINDS OF CHANGE" ... video confirmed
1. "Scholar's insight"; 2 skill points instead of 1 from skill books
2. "Companions' insight"; Attacks spells and shouts do no damage to followers
3. "Lover's insight"; +10% damage to opposite six, 10% better prices from opposite six. Stacks with Speech perk and Agent of Dibella.
"The (Sallow/Shadow) Regent" (White Ridge Barrow)
1. Combat skills 10% more powerful; weapons deal 10% more, heavy armor protects 10% more, smiths are 10% more effective, etc.
2. Spells costs 10% less and enchantments 10% better.
3. Thief skills 10% better. Better sneaking, alchemy, pickpocket odds, light armor's defense, speech and lockpick.
"UNTOLD LEGENDS" (Benkongerike) ... video confirmed
1."BLACK MARKET" Summon a Dremora to act as a trader (Gold appears a measely 2K, sells ebony and glass items in one video, not affected by perks)
2. "DREMORA BUTLER" Summon a Dremora to carry your excess items (Weight capacity unknown?)
3. "BARDIC KNOWLEDGE" Magical drum appears, acting as and AoE buff to friendlies' stamina regen (Magnitude?)
"Epistolary Acumen" (From Main Story in dumner ruins with telvani guy)
1. Unrelenting force does more damage and has chance to disintegrate target
2. Fire breath spawns fire wyrm from any enemies killed for 60 seconds to help you.
3. Frost breath freezes enemies.
"Unearthed / Filament & Filigree" (Kolbjorn Barrow)
Secret of Strength — Power attacks cost no stamina for 30 seconds.
Secret of Arcana — Spells cost no magicka for 30 seconds.
Secret of Protection — You take half damage for 30 seconds.
"The Hidden Twilight" (Tel Mithryn – Given by Neloth)
Mora's Agony — Summons a field of writhing tentacles that poison foes.
Mora's Grasp — Freezes the target between Oblivion and Tamriel for 30 seconds, making them immune to all damage.
Mora's Boon — Fully restores your Health, Magicka, and Stamina.
"WAKING DREAMS" (After last boss)
Perk respec, as described below, 1 dragon soul to reset a perk tree. Doesnt affect skill level. No way to reset HMS.
Also, this is probably not black book related but wikis are listing the following 'Blessings'. Temporary or full time passive?
Blessing of Azura — Resist 10% of magic.
Blessing of Boethiah — One-handed weapons do 10% more damage.
Blessing of Mephala — Prices are 10% better.