Her abilities, while generically powerful, work great with Vehicles
In this release, it represents travel-related abilities as well as some combat abilities
Varchild, Betrayer of Kjeldor could be fun in some sort of group slug deck where you give your opponent tokens but in a harmful manner (maybe with something like Trespasser's Curse on the battlefield), although she might be better in the 99, since mono-red is pretty limiting
Your opponents will rarely be able to interact with it unless theyre using the likes of Stifle
Put a time counter on this enchantment for each creature that phased out this way
I imagine if some sort of self-mill and/or sacrifice space connects well with energy, the Marvel would be great for its static ability alone