Im admittedly at a loss for exactly what I would personally do with the nightmare beast as my general, in that just about any creature or mechanic with counters in the rules text could be a contender here
No damage from pain lands or shock lands, no coming into play tapped in the first few turns and that's it
Beyond that, Commander staples like Ancient Tomb and Reanimate also debuted in this set
Theres a special corner case when a room becomes a copy of another room
In terms of full cards, I pulled the following lineup across 55 packs: 6 Illustration Rares 3 Ultra Rares 1 Special Illustration Rare That makes the pull rates for Illustration Rares roughly 1 in 9, with Ultra Rares at around 1 in 18, and Special Illustration Rares sitting at roughly 1 in 55 packs
Espeon ex from Unseen Forces gives you plenty of ways to manipulate the game in your favor, especially with its Devo Flash Poke-Power