If they don't, then they become Cie'th, or monstrosities
Honorable Mentions Sven Reindeer Steed and maybe Try Everything fit in this weird slot where in specific situations they are incredible
For example, if you have two Nyxbloom Ancients on the battlefield, you'll get nine times the original amount and type of mana
The other option is to take advantage of the direct damage, which is good in its own right to either finish off a damaged character or get them within range to be banished but also works with the likes of cards that benefit from being damaged - such as Scroop, Backstabber - that benefit from healing damage, like Rapunzel, Gifted Artist, or from damage being dealt: like Beast, Relentless.
Now he stumbled upon THE Vintage budget format: Value Vintage
Players can see what a deck may look like with specific cards and if it will work out for their personal strategies