Agents of SHIELD season 7 is, currently, airing on ABC, and this would be the final installment of the series. The final run keeps on delivering fun surprises, with Patton Oswalt being on the Great Depression episode. And since time-traveling is one of the essential components of the series finale, there's a possibility we're going to see more surprise appearance along the way.

Agents of SHIELD season 7 could take on a different approach when adding new and familiar faces, though everything depends on the guest stars' availability. What's clear now is that there would be substantial Agent Carter crossover coming. But, the question now is: is there something more beyond that? That could be possible within the final run.

Speaking to Collider, series star Clark Gregg, who plays Coulson, has something to say about the particular subject. In terms of Oswalt's appearance, he said it wouldn't be a good final season unless the actor was there. Gregg said Oswalt was the "secret weapon" that showed up and made the better all the time. His appearance in the finale installment made the story even more interesting.

When it comes to Agent Carter, Gregg noted he is excited to have Enver Gjokaj in Agents of SHIELD season 7. Gjokaj will be reprising his Agent Sousa role, and it's exciting to see what he could bring within this world. But beyond these significant appearances, the actor also teased a few other surprises along the way, which include "interesting versions of past people"

Gregg didn't further tease as to who these appearances would be, but others speculated that some former series regulars will appear in the series' final run. This is also a way for the show to tie up some of the loose ends since the beginning. It would be interesting to see these appearances, and after all, this is a chance to see everyone coming together for one last time.

Meanwhile, Gregg also talked about how things wrap up in Agents of SHIELD season 7, and whether or not fans will be satisfied with it. He said they travel through different decades in the series finale and they try to deliver what those decades represent -- especially in terms of style and tone. They put some cast members in different time periods, wherein diversity is a challenge for people.

Gregg said they make the most out of that and have fun with it, given that this is already the final season. The actor further noted that they have nothing to prove to anybody but themselves. The series has been on-air for several years now and it managed to deliver fun and interesting stories. And for those who watched it from the start, the ending may feel satisfying.

Agents of SHIELD season 7 airs every Wednesday night on ABC.