Hmmm... I have a couple that I'm aware of, and I suspect there are more I haven't spotted yet. Do tropes count? (This is for both my lit work and my visual stories, since they pop up in both)
- Not quite an image, but characters who end up with a surrogate father/uncle figure. - Appearances are deceiving; things are usually more than the sum of the parts you can see - gender ambiguous characters - Stereotypically bad powers don't mean the wielder is a bad person, and vice versa. - The more useless someone's abilities seem at the outset, the more critical they turn out to be (It's not the gun toting, badass captain of the ship who handles diplomacy with aliens, it's the intern who's good with kids and the human resources employee who can translate languages who end up saving the day, for example.) - The phrase "You've got to be kidding me," as well as variations on "not again" - Places where time stands still, particularly in relation to: - Mirrors as a metaphor for the ceaseless/eternal and dreams - Sunlight (usually 'golden' or filtering through treebranches) as, again, a sign of (happy) dreams, eternal moments, or the afterlife
Less seriously (more as a case of Author Appeal, I suppose): - Hapless protagonists, A la Rincewind of Terry Pratchet's "Discworld" series or the main character of "A Hitchhiker's guide to the galaxy" - There's at least one BAMF lady, one offbeat trickster character who doesn't conform to social norms, and one slightly helpless guy.
Those are the big, obvious ones. There are some minor themes such as the future being unknowable and there being other universes/life on other planets that show up a lot, but I doubt they really qualify as motifs.
I've always found that a very common thing that pops up in my work is the concept of Humanity. What it means to be Human. Even the characters that are not 100% Human feel and act the same way as the other characters, which raises the thought that one doesn't strictly need to *be* Human to BE Human.
There's also smaller motifs, such as rising insanity, battles that cannot be fought alone, and even smaller symbols that crop up here and there.