Which piece of lore that Daggerfall added was your favorite?

[Morven Ashwing]

Which piece of lore that Daggerfall added was your favourite?

[Imbalance]

I'm sensing a theme, though you may want to edit the content of your post.

Daggerfall may not have introduced the world of Tamriel, but it really got the ball rolling. Establishing conflict with various and long lasting effects with the main quest ending in a time warp might have been a copout, but they made a firm foundation out of it.

[Morven Ashwing]

I'm sensing a theme, though you may want to edit the content of your post.

Well, that was embarrassing. Surely this can't be spamming when one post cannot be dedicated to the separate questions...

Daggerfall may not have introduced the world of Tamriel, but it really got the ball rolling. Establishing conflict with various and long lasting effects with the main quest ending in a time warp might have been a copout, but they made a firm foundation out of it.

I can't contradict you there.

[Jormungandr]

Yeah, Daggerfall added so much that Arena feels more like just a generic fantasy game. I mean, Arena may be the first game in the series, but to me Daggerfall is what actually started the series to become what it is today.

Favorite addition, then:
Absolutely everything about the Daedra! It was neat to have a detailed pantheon of not-nice-nor-particularly-good creatures as godlike beings.
Also, as something that is unique to DF, I enjoyed Atronachs being wizard-made constructs/golems instead of lesser daedric creatures.

[Morven Ashwing]

Absolutely everything about the Daedra! It was neat to have a detailed pantheon of not-nice-nor-particularly-good creatures as godlike beings.
Also, as something that is unique to DF, I enjoyed Atronachs being wizard-made constructs/golems instead of lesser daedric creatures.

True, both these aspects are anything but generic.

[AutismFanaticism]

Adding on to what Jormungandr said, pretty much the inclusion of such a detailed religious system, with both good Gods/Divines/Aedra and evil Demons/Daedra whose worship is outlawed (for the most part) would be among my personal favourite Daggerfall lore-additions. In fact, I follow a religion directly inspired by the Nine Divines of Imperial worship. Ebonarm is also pretty cool, though I wish Zenimax wasn't editing him out of ESO. However, it is odd that the Bretons would choose to worship Ebonarm over Talos/Tiber Septim (which can be blamed on the devs; Julian LeFay clearly never thought that anyone would worship a once-mortal-man as a god (obviously, he isn't Christian)), considering that one theory holds that Septim was born in Alcaire, and even one of the regional holidays, Tibedetha in Alcaire, is devoted to honouring Tiber. That's another piece of lore I really enjoyed in Daggerfall: regional, as well as Empire-wide, holidays, which have not been seen since, and which sorely need to return, for that extra bit of immersion.

Excuse me for going off-topic, but, adding on to another thing Jormungandr said, personally, I enjoy Arena, as well as Daggerfall, and all the other TES games: each has its own merits, as well as its drawbacks (I actually enjoy Daggerfall's dungeons). Something I don't think a lot of people know: in Arena, one Era was a period of one-thousand years, instead of changing based upon an emperor's whims or after certain events that had Empire-wide consequences (a la Oblivion), hence the 'typo' in the opening screens; the world of Arena also had only one moon, instead of the two that Nirn had from Daggerfall onward.

[Morven Ashwing]

In fact, I follow a religion directly inspired by the Nine Divines of Imperial worship.

That must be cool.