When creating unique decks or sets with customized mtg rare find abilities, its important not overlook these determining factors such as casting-cost
Canoptek Spyder might be expensive for a 60-card format considering it's five mana and doesn't just win the game, but every Commander deck with Vehicles in it should be running this card
cards in graveyard for mechanics like delve, escape, and delirium
The key is that custom doesnt mean from scratch and painful. You can start from an existing card and edit from there, which is the fast lane
As opposed to cards like Moat that just leave your opponents creature in play (until the can find an answer), The Abyss will destroy these creatures, and even prevent your opponent from continuing to play creatures (on account that they will eventually be sacrificed)
Hostage Taker Butcher creatures like Fiend Hunter and Brutal Cathar can exile others for as long as they remain on the battlefield, but what if there was one that let you play those cards as well