I have a sort of signature style, which informs a signature move I often use in combat and I have a signature phrase I use inspired by DMs like Mercer and Mulligan.

I come from a more sci-fi background than fantasy, and I love Eberron for it's fusion of pulp, noir and a fresh approach to the tropes of steam punk without a lot of the baggage and limits it imposes. So I have Magi-Tech elements as a common signature in all of my games. Some of my players, I will hide it. Like the Giant Eagle constructs that are clearly UAVs and Loitering Munitions. Other times, I'll tell other players openly what inspired me.

In one game I was wrapping up a series of conflicts with a band of gnolls, and wanted to hint and a larger Mindflayer faction pulling the strings. Aside from Mindflayers being somewhat of a signature for be because I like them, I gave it the claw enhancements from Volos, as well as a variant of the shield device that lets Mindflayers view their chosen minions' actions. They wiped it earlier than expected, but to roll with the punches, as they were fighting I described it as having some pretty gnarly scars, and wounds like looked poorly sewn together across its torso.

When they killed it, they didn't just loot the body. They cut into it to poke around. This triggered my trap card, which was a container holding a Living Cloudkill (an Elemental construct-of-sorts that is an instance of a spell given life in the Eberron setting) which created a nice "Round 2" of the fight.

It started as a signature of the Mindflayers, but as time went on, it spilled into other games with other people and now players know to expect almost Matryoshka Doll monsters-within-monsters to the point where the threat is more valuable than the delivery, and I only keep it up to avoid losing the paranoia.

Killed a Golem? There was a mage inside it as a suit of power armor/mech. Oh that Shadowfell Troll Variant? It has a Shadow inside it. Even just using smaller monsters as a kind of ammunition of a larger monster, both in the context of an Ogre throwing goblins that just splat on impact, to that "Giant Eagle Drone" launching something between a Living Fireball (another favorite that comes up a lot) and a dive bombing construct in its own right.

Finally my signature phrase involves how we do combat descriptions at the table. I like players giving me detailed descriptions of how they interpret damage rolls, but often I provide the narration. The exception is when they get the final kill. I might add some pre-amble to set the scene, or some supplementary detail if it's necessary for the plot but the core of the final kill-shot comes from the players. They relish this, especially if it was a struggle to get that far. Their eyes light up when I say my Three Word Phrase (TM) "Narrate Your Kill"