Many others can simply be found exploring. Some of these have unique effects on them that you will not find on other items (or only 1-2 others) and some of these can even be disenchanted to learn those special effects; so even if you don't want the item itself you may want to use the effect. This list is not complete but comes from skimming through the search results from the PC version developers console:
Weapons:
- Alessandra’s Dagger
- Amren’s Family Sword
- Steel Battleaxe of Fiery Souls (is apparently non generic)
- Aegisbane
- Bolar's Oathblade
- Bow of the Hunt
- Eduj
- Firiniel's End
- Froki's Bow
- Grimsever
- Notched Pickaxe (Minecraft reference)
- Okin
- Red Eagle's Fury and Red Eagle's Bane
- Trollsbane
- Woodsman's Axe
- Wuuthrad
Armor:
- Jester's Garb
- Helm of Yngol
- Konahrik
- The Forgemaster's Fingers
- Gloves of the Pugilist
- Movarth's Boots
- Predator's Grace
- Shield of Ysgramor
Clothing/Jewelry
- Charmed Necklace
- Nightweaver's Band
- Muiri's Ring
- The Gauldur Amulet
- Necromancer Amulet
Dragonpriest Masks (most are aquired merely by dungeon diving and boss-killing on your own):
- Krosis
- Morokei
- Hevnoraak
- Nahkriin
- Otar
- Rahgot
- Konahkrik
- Vokun
- Wooden Mask
Staves:
- Eye of Melka
- Hevnoraak's Staff
- Sild's Staff
- Staff of Jyrik Gauldurson
- Staff of Tandil
Staff of Magnus
Some of these are quest rewards. The Dragon Priest masks are not though a few 'three' are found during quests. Some of these (such as the Red Eagle items) have a quest to find them for the sake of finding them - you read a book and this provides information about it and marks it on your map; Grimsever similarly can be lead to by a quest. The quests are not nescessary to discover the items though.
Most of the 16 unique daedric artifacts (some of which additional unique alternatives if you chose different solutions to those quests) come from quests you get from exploring and finding either special items or shrines. There are some cool leveled artifacts such as Chillrend which do not require quests to find. They are leveled, but generally quite good at the level you find them unless you per-sue enchanting and smitthing faster than all your other skills.
These include:
- Chillrend
- The Pale Blade
- Gauldur Blackblade
- Gauldur Blackbow
