Stormchaser's Talent is one such Class: If it exits and then returns to play, you'll get a second 1/1 blue Otter token, and if it gained a level before being exiled it will be reset, and you'll be able to use the second ability to fetch an instant or sorcery from your graveyard a second time
Since you are using an alternative cost to cast a spell from exile this way, you can't pay any other alternative costs
Its a solid instant-speed removal card that can scale for longer games
The natural inclusions in any deck playing Darcy are Mishras Bauble, Unholy Heath and, if paired with Blue, Expressive Iteration and Counterspells
This can come in handy to deter aggro decks
Control decks have their place in the game, and interaction is needed in Commander, but sometimes its too much