While all these cards are powerful, a plethora of colorless lands (Myriad Landscape, Ghost Quarter, Homeward Path, etc.) and utility cards (more Modular creatures like Arcbound Reclaimer & Arcbound Overseer, Liquimetal Coating to help your non-artifact creatures pick up +1/+1 counters from fallen Modular creatures, and Contagion Clasp for repeatable Proliferate) can readily fill the gaps
My general preference is to pick up a mana dork, then a Ghostly Prison, then Sanctum of Stone Fangs, though you can adapt to whats in your opening hand and the most pressing threats on opposing battlefields
It feels strange that this collection only has four cards
The -2 ability tutors artifacts and puts them into play, while the +1 ability untaps two artifacts
Based on the latest market prices tracked on TCG Stacked, Teferi, Who Slows the Sunset is worth about $4.96 USD for a regular copy and $3.61 USD for a foil copy
Its a 5-color removal powerhouse that penalizes opponents for attacking you because then theyll lose a nonland permanent when you attack them back