Basically phase out means the creature and everything attached to it ceases to exist -- it doesn't change zones, it just goes poof , totally gone and can't be interacted with in any way, until it phases back in (exists again) at the beginning of its controller's next turn
Some good sites to get ready-to-print PDFs with MTG look-a-like proxies are MTGpress and Deckrealm
The rotating sets include Innistrad: Midnight Hunt, Innistrad: Crimson Vow, Kamigawa: Neon Dynasty, and Streets of New Capenna
This variant of Avacyn, Angel of Hope is likely to be divisive, and the thing that I love about it, how small Avacyn looks under the gaze and grasping hands of some unknown monster, is exactly what others will despise
Submerged Boneyard
Commanders Plate or any of the other notable Swords are great options