Watermark: Planeswalker DailyMTG Story Spotlight Illustrated by Kieran Yanner Standard Not Legal Alchemy Not Legal Pioneer Legal Historic Legal Modern Legal Brawl Legal Legacy Legal Comp
The cost reduction for artifacts and creatures sacrificed earlier in the turn will apply even if you don't sacrifice any as an additional cost
Obosh, the Preypiercer Suggested Cut: Combustible Gearhulk The Lord of Pain, as well as other important damage dealers in this deck like Brash Taunter, Descent into Avernus, and Vial Smasher the Fierce, all happen to have odd mana values
And it's a pretty interesting sacrifice commander
After that though, you could consider a lands-matter sub-theme, playing multiple lands a turn to stack up the triggers
This makes it easier to attack and not risk dying on the crackback