Urza (cEDH) (EDH / Commander)

The main strategy of deck is assembling a combo of infinite mana in order to win the game in several different ways.

The infinite mana combo can be assembled in four ways. Some advices. If you have Urza, Lord High Artificer on battlefield is better because you can tap artifacts that are not mana rocks to produce blue mana. The second suggestion is avoiding to activate the combos with lands because you can use them to cast counters if opponents try to disrupt your game plan. Third advice, use artifacts and mana rocks because they are affected by the combos. Finally, pay attention on the mana: your aim is accumulate mana exceeding it with the combos.

The four ways to assemble infinite mana combo are the following:
1) Isochron Scepter + Dramatic Reversal;
2) Isochron Scepter + Narset's Reversal + Dramatic Reversal (in this case you imprint Narset's Reversal with the scepter and then you cast Dramatic Reversal to copy and bounce it in the hand);
3) Isochron Scepter + Dramatic Reversal + Copy Artifact + Narset's Reversal (it works as the second condition, but here you "duplicate" the scepter with Copy Artifact and imprint Narset's Reversal);
4) Grim Monolith/Mana Vault + Power Artifact.

After setting the combo, you can win inserting one of the following card:
1) Walking Ballista: infinite damages wherever you want;
2) Codex Shredder: mill every opponents tapping and untapping the codex;
3) Urza, Lord High Artificer: you can activate the ability of Urza in order to find one of the two aforementioned cards;
4) Sensei's Divining Top: if you activate the second ability of Sensei's Divining Top, on the stack you can activate infinite mana combo to untap all permanents and produce (always on the stack) an sufficient amount of mana to activate the ability of Sensei's Divining Top nth times in order to draw entire deck.

The deck is almost a control/stax deck with the aim to take under control the opponents' threats and slow down the game to have the possibility to search for the combo pieces. The most powerful aspect of the deck is the ineffectiveness of stax pieces on you: with Urza, Lord High Artificer you can tap Winter Orb, Static Orb and Trinisphere at opponents' end phase and untap all permanents that you want at beginning of your turn. In addition, The Tabernacle at Pendrell Vale does not impact on you because of reduced number of creatures that you play (in case of having Urza on the battlefield, it is very easy to elude the effect of the tabernacle).

This version of the deck is quite performing. I avoided adding Thassa's Oracle combos (auto-mill strategy as win condition) because I think that it adds nothing to the previous described combos and the lack of the black color can make it more difficult to realize. Regarding the combo with Capsize (a card that you use with Isochron Scepter combos to bounce everything on the board except your permanents), I excluded it because a 3 manas card increases the mana curve significantly (from 1.87 to 1.90-1.93). Finally, I cut off another interesting combo composed of Sensei's Divining Top + Future Sight + Etherium Sculptor: with the three cards on battlefield, you can switch Sensei's Divining Top with the first card of your deck, re-cast it gratis for the effect of both Future Sight (you can cast the first card of your deck) and Etherium Sculptor (artifacts you cast cost 1 generic mana less), and draw entire deck in order to find combo pieces. The reason is double: firstly, the increment of mana curve for the presence of Future Sight (that is also useless out of the combo); secondly, tutoring an enchantment is very difficult because the only suitable tutor is Intuition. I preferred to substitute Future Sight and Etherium Sculptor with Walking Ballista and Trinisphere: the first is an alternative win condition and the second is an additional stax piece.

The power level of deck is cEDH: it also justifies some expensive choices and the low level of mana curve.