Spatial Merging gets errata to read "Place both of them in the same slot on the planar map" instead of "Simultaneous planeswalk to both of them." My main guiding principle for these house rules was that phenomena are random, one-time events, so it was aesthetically unappealing to have them sitting in a spot, waiting to be triggered
While a lot more efficient than Sprout Swarm it is more easily disrupted and needs more tools to be able to get out of control as Swarm can on a bloated stagnant board
This is especially important if the card is connected to any kind of interesting origin story (like most of the cards above)
Over the past few weeks, I'd gone over Chulane, Teller of Tales, Korvold, Fae-Cursed King, and Alela, Artful Provocateur, in that order
As a deck can only contain cards within the chosen commander's color identity, the more colors within a commander, the more options you have when selecting cards for your deck
Make sure the deck list is sorted by "Custom" to see each category