In your own space, share your love for a trope, cliché, kink, motif, or theme. (Or a few!) Tell us what makes it work for you, and why it appeals to you so much. Talk about what you like to see in fanworks featuring that theme most. Feel free to include recs and examples!
Here are a few. Most are DW-specific.
Chameleon Arch: I love stories that explore the differences between humans and Time Lords, and what better way than with the chameleon arch? I should note that what I really love about this is the process of discovery - as in the episode, John slowly discovering that he's the Doctor, and the fun of the audience figuring out what's going on ahead of the characters - so I also love other memory-wipe tropes.
Multi Doctors/companions: Doctors meeting each other are the best. So many possibilities: Will they like each other? Will they hate each other? Will they work together? Will the First Doctor have to show up and knock their heads together? Special mention of "Peri and the Piscon Paradox", because if you haven't heard this audio, WHY THE HELL NOT???
Doppleganger crossover: I shall admit just how shallow I am: I especially love DCs involving David Tennant characters. I don't know if it's simply because I love DT, or because he's the only actor who has multiple diverse characters that I like. (Yes, if you haven't already figured this out, my fandom interests are very narrow.) I just like imagining more than one DT on the screen at once, and the clashes between his vastly different characters would be epic. I mean, come on, DI Hardy meeting Peter Vincent? I cannot imagine that the building would still be standing afterward. (P.S.: Tencest occupies a special place in my heart.) Maybe someday I'll get sufficiently familiar with someone else to care about DCs with them. Thirteen and Beth Latimer, maybe?
Psionics: I'm a fan of superheroes and superpowers in general (especially Marvel comics and MCU, and Sanderson's "The Reckoners"), but my favorite is psionics: telepathy, telekinesis, empathy, etc, though not so much precognition. I don't know why. I have a lot of problems not using psionics in my stories.
???: I don't know if this trope has a name, but I love it when the heroes encounter a situation which, all the way through the story, seems to be an evil orchestrated by some twisted villain(s), and it turns out that the antagonists were actually doing something innocent, but it looked evil from the outside. (Not when they're doing something innocent that turns out to be evil to someone else - that's completely different.) The Testimony from "Twice Upon a Time" are a good example of this.
Honorable Mention: De-aging: Young versions of canon characters can be so fun! I loved the episode "Rascals" from ST:TNG, with Picard screaming, "I want my father! Now! Now! Now! Now! Now!" I picture the mature character (and the actor) doing things like that and just laugh... I also just saw the episode "Fragile Balance" from Stargate SG-1, with young Jack O'Neill, and while the story itself wasn't the best, the actor who played Jack was fantastic and he made the episode.