Close games, even ones you lose, are always the best and most memorable.

There's nothing wrong with liking a generic artifact you put into most of your decks. Without knowing your decks, I would take staff over bell because of the added versatility. It helps their the same mana value but beware the life loss from the staff can add up.

However, most decks would benefit from a synergistic draw source rather than a generic one-size-fits-all card. Such as adding Well of Lost Dreams in a life gain deck or Idol of Oblivion in a token deck.

A lot of this can also be meta dependent. Going with some generic cards will also tend to lower the power level of your decks (which can be a good thing).

Definetly swap out for Temple Bell. Outside of group hug it is terrible. Your getting 1 card and giving your opponents 3 cards.

Ichor Wellspring: Are you bouncing or recurring this? Not worth it otherwise.

Unwinding Clock: Not enough artifact lands or Mycosynth Lattice.

I'm a big fan of the Marble Diamond cycle but with power creep/more efficient options, they are in almost none of my decks.

Land Tax would be the best addition. You could also consider Deep Gnome Terramancer since he can potentially get you multiple lands per turn cycle (or potentially nothing but same if you have the most lands for a ton of white cards).

You could consider swapping out Marble Diamond with any other 2 cost rock that doesn't enter tapped. There's Arcane Signet and Fellwar Stone for white or Everflowing Chalice if you end up having more than 2 mana you can spend.