add in an extra subtle element (think the high pitched synth that comes ontop of the horns in on the third drop of RL Grime's Tell Me, it's a relatively small addition and the rest of the drop is essentially copy pasted from the first one, but changes the feel massively because of the sudden addition of a sharp high-end frequency to the song)

stutter or gate the initial few notes for the first couple beats or add some pre-delay of elements of the drop fading in for a sec BEFORE it hits to give it that "it's comin' back" anticipatory feeling

make a bassline kick in a half/quarterbar later than it does in the initial drop

fuck around with the drums, add an extra kick, or remove one and make them heavier and take up more space, change the hi hats, double-time em, stuff like that

little subtle things are enough, where's it's just enough of a change to notice the difference, but juust enough.

the first drop is where you sell the song to somebody mentally, the second and/or third ones are where you play with expectations to keep it interesting but as long as you've sold it in the first place just little touches to keep it fresh is all it takes to keep it from feeling stale or lazy.

don't be afraid to go completely out there and totally switch it up, even just surpsise drop to/from house to trap or dancehall or whatever, BPM change, go nuts, and just keep one or two elements of the initial drop so it still feels like the same song and not someone accidentally hitting skip

this is obviously harder to pull off but if it's done well it's one of those things that makes people lock eyes up in da club and go "daaamn" at each other and as a producer for dance music i think that's what everyone's ultimate goal is