what are mtg showcase cards MTG's March Of The Machine Remembers Why Frames So Special Sleeper Agents Awaken! | Magic:

Call for Backup (red/green/white) Bright-Palm, Soul Awakener

B: Syr Cadian, Knight Owl gains flying until end of turn

They adjust the environment exactly so that they can field test how the players are going to respond to it

This card can be a decent commander for sacrifice decks, but it can also fit right into the 99 of most Rakdos decks

Can I take them out in response to a spell to save my creature (for example, I'm wearing white colored contact lenses and my opponent plays Execute)

In fact, as I was going through the list, I did hit a few spots where it felt like making cuts was a bit challenging, which I think is a testament to the improved quality of these recent decks