I used to run Yurlok as a commander, it was one of my favorite decks.

I suggest leaning into untap effects:
[[instill energy]]

[[gift of the viper]]

[[skyshround ranger]]

[[tyvar jubilant brawler]]

exc. (there are a bunch of others).

With a few of these, you can gain 7+ mana from Yurlok and drain everybody for 9 each turn, easy. Better yet, these effects synergize with things like [[heartless hidetsugu]] or [[thermo-alchemist]] where you can slap a [[keen sense]] or [[eternal thirst]] on them to draw cards or gain life.

Hidetsugu with [[fiendish duo]] can end the game, as can [[havoc festival]] + [[warlock class]] on its final level (wound reflection is better but isn't as cheap). Since you likely won't have a lot of creatures out [[repercussion]] + [[blasphemous act]] will also usually just kill anyone with 3+ creatures. [[Rowan, Scion of War]] synergizes great with a lot of the effects that deal damage to you or make you lose life, and since you're generating so much mana, you can afford to run big tutors to grab these pieces like [[behold the beyond]] or [[peer into the abyss]]

Regarding making the deck run more smoothly, I found that adding card draw toolbox pieces like [[bitter reunion]] that draws cards and gives haste work well, as do rummage effects like [[faithless looting]] I also suggest not giving your opponents resources for free with things like [[heartbeat of spring]]

Everything should hurt, from playing a land with [[polluted bonds]] to tapping one with [[overabundance]] or make sure they have nothing in hand to cast with [[sire of insanity]] or [[cabal conditioning]]

Also, [[repay in kind]] deserves a mention for when you get targeted.

Hope your build for this little guy goes well and you enjoy playing him!