Constructs generally want other constructs so here are some solid ways to construct constructs, with both commanders and non-commanders: Urza, Chief Artificer, Mishra, Eminent One, Vihaan, Goldwaker, Dollhouse of Horrors, Digsite Engineer, and Simulacrum Synthesizer
Shout out to our final common, Tavern Brawler which will let your Commander exile the top card of their library their upkeep and then cast it and the Commander gets power boosts equal to the mana cost as well, so they play well together
This was awful last time and it will be here too
Japan Showcase cards have an overall 10% chance of appearing in a dedicated slot, and of one our of 10 of those that are opened are fracture foils