Much like how Eclipse seems to be inspired by a major detail in Think Different, there are details in some briefings that can be turned into ideas for entire side missions for Covert Ops. Here are some I've found:
Rashidi has been captured, and by our very own Soviet army! It turns out both and Allied and Soviet armies in Africa were very concerned about the Scorpion Cell, and the Soviet African Expedition, hiking the trail, eventually set a trap for him! - Killing Fields briefing
A Soviet mission that involves the capture of Rashidi. Could be a great mission to introduce the Drakuv (or at least a prototype since apparently it does not appear in Act One).
While a significant bulk of our army is now part of the expedition force, the remainder of it is still holding their own in the defense of England, but they won't last much longer...Assuming that Yuri is the one currently holding the MIDAS, it's very likely that, once the Gladius System falls, Yuri will fire it at either the remainder of the London Fortress, or the expedition force itself. If that happens, we're doomed, but we must push forward. - Bottleneck briefing
While the Allies are distracted with our naval and aerial armies coming along the coast... - Godsend briefing
An Allied mission that uses Sunlight's layout but instead of Soviets, Epsilon armies will be invading. And instead of a "destroy all" kind of mission, it becomes a defense mission with a timer. Or it could be a role reversal where the player commands the Epsilon invasion force.