List of a few ones.

[Sodomir]

As for the first question, I agree completely. While Sodomir is right that an upped pillar is great to win because it's a free thousand , an unupped pillar is a waste of a spin.

Also an unupped Pillar is an advantage. You get 5  form the spin and have new card, and pillars always need. Even when sell it it give 4  . So it is better to get a pillar than nothing, isn't it?

[Monox D. I-Fly]

Wait a moment... If Nymphs can only be acquired via tournament, so I can't have them from the spinning after winning a match, even though my opponent has several of them?

Yup. They become relics in the spins.

Oh yeah, I've ever gotten two of them and sold one. I'm saving the other one as collection. Have they be sold? Can they be upgraded? What happens if I try to upgrade it?

[RootRanger]

Relics are completely useless in battle and should be sold. Upgrading them is a waste of money because you will never have a use for them in a deck. Their only use is selling them for electrum.