Fanfiction.net could also be a good place. Although its interface might not be as modern as AO3, it still has a lot of fanfics. Look for the relevant sections related to the shows or comics these characters are from and then search specifically for the Alex Danvers x Imra pairing within that section.
One common trope could be the 'enemies to lovers' trope. Maybe they start off on opposite sides due to their different loyalties in their respective storylines, but as they get to know each other better, they fall in love. For example, if their groups have some sort of conflict, but they find common ground.
One question could be whether the characters' personalities are accurately depicted in the cartoon. Usually, they try to match them closely, but sometimes there might be differences.
Well, in a breach of trust comic, it could be telling a tale of a hidden secret that comes to light, causing a rift. Or it could be about a character's struggle to regain lost trust. The possibilities are endless, depending on how the author decides to spin the story.
Donatello in the TMNT cartoon is known for his intelligence and technical skills. He's the brains of the team, always coming up with gadgets and solutions to problems.