Casting non-creature spells with a cost of three or more while Yshtola is in play causes each of your opponents to lose two life while you gain two in return
Phantom Train becomes a spirit creature when you activate it, and you know what's really good against spirits
Magic: The Gathering Original Release Date August 5, 1993 Publisher Wizards of the Coast Designer Richard Garfield Player Count 2+ players Age Recommendation 13 years and up Franchise Magic: The Gathering
Your creature has to connect with the Avenger on it for you to dump an aura, but the good news there is if your creature connects and you get to trigger the ability on Holy Avenger, you can be reasonably sure it's going to stick around (or it probably wouldn't have connected at all!) Oh, by the way, it comes with double strike, which means everything I just said above happens twice a turn
You could also go artifacts or enchantments, since there are also many artifact creatures and enchantment creatures, especially ones that would give you additional cost reduction