Rebbec, Architect of Ascension Rebbec, Architect of Ascension grants a pretty wide swath of protection from spot removal, which is a useful service for the artifact commanders that might want a spot of white to partner with this artificer, like Silas Renn, Seeker Adept, Ich-Tekik, Salvage Splicer, and a few others
Bellowing Aegisaur Cacophodon Frilled Deathspitter Imperial Ceratops Needletooth Raptor Overgrown Armasaur Polyraptor Ranging Raptors Raphael, Ninja Destroyer Raptor Hatchling Ravenous Daggertooth Red Hulk Ripjaw Raptor Siegehorn Ceratops Silverclad Ferocidons Snapping Sailback Sun-Crowned Hunters The Incredible Hulk Trapjaw Tyrant Urban Daggertooth
Everything else gets out of the way
At the extreme, you might eschew one or more colors entirely
If you somehow control two Elesh Norns, a permanent entering the battlefield causes abilities to trigger three times, not four