Well, if you want to play a lot of instants and sorceries, you may wish to run some more cards that can refuel your hand. Perhaps a few wheel effects, as those also play well with Urabrask's saga side. [[Reforge the Soul]]/[[Raphael's Technique]]/[[Wheel of Misfortune]] (can be a bit shaky)
#Urabrask
austere fable
prisma smeltBOT
Sorcery
Each player discards their hand, then draws seven cards.
Miracle 
(You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)
In a wave of spells called the Cursemute, Avacyn cleansed the world with divine fire.
Instant
Sneak 
(You may cast this spell for if you also return an unblocked attacker you control to hand during the declare blockers step.)
Each player may discard their hand and draw seven cards.
"Change of plans!"
austere fable
[[Magus of the Wheel]]/[[Wheel of Fate]]
prisma smeltBOT
Creature — Human Wizard
, 
, Sacrifice this creature: Each player discards their hand, then draws seven cards.
"Fate is not as fixed as you might think."
3/3
Sorcery
Suspend 4— (Rather than cast this card from your hand, pay and exile it with four time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
Each player discards their hand, then draws seven cards.
austere fable
Rituals may also be worth considering. [[Seething Song]]/[[Mana Geyser]], that type of thing.
prisma smeltBOT
Instant
Add .
Vulshok mana rituals echo the day when the red sun burst through Mirrodin's surface to take its place in the heavens.
Sorcery
Add for each tapped land your opponents control.
The Quicksilver Sea hissed and bubbled at the indignity. The Vulshok shaman just smiled.
austere fable
I see that you wish to make things fit to theme, hence the large amount of Phyrexians. But you may also be able to do something similar, using artifacts to fuel your instants or sorceries.
Now warning: this may stretch the theme a little bit.
There once was a goblin on Mirrodin, named [[Slobad, Goblin Tinkerer]]
He was eventually turned Phyrexian, later Urabrasks handiman: [[Slobad, Iron Goblin]]
If we accept this kind of goblin/phyrexian overlap, we might be able to stretch that a bit into cards like [[Trash for Treasure]] or [[Goblin Welder]].
prisma smeltBOT
Legendary Creature — Phyrexian Goblin Artificer
, Sacrifice an artifact: Add an amount of equal to the sacrificed artifact's mana value. Spend this mana only to cast artifact spells or activate abilities of artifacts.
Once he fought to save Mirrodin. Now he fights to remake it.
3/3
Creature — Goblin Artificer
: Choose target artifact a player controls and target artifact card in that player's graveyard. If both targets are still legal as this ability resolves, that player simultaneously sacrifices the artifact and returns the artifact card to the battlefield.
"I wrecked your metal guy, boss. But look! I made you an ashtray."
1/1
austere fable
Now we could use this to turn phyrexian influenced artifacts like [[Mycosynth Wellspring]], [[Ichor Wellspring]] into [[Gate to Phyrexia]] for example.
austere fable
Oops, I meant: [[Portal to Phyrexia]]
prisma smeltBOT
austere fable
In addition to this, there are some instants/sorceries that reward you for having artifacts to sacrifice. [[Demand Answers]], [[Gleeful Demolition]], [[Kuldotha Rebirth]] and [[Shraphnel Blast]]
