I listed everything I could think of off the top of my head and through quick searching. I included a variety of genres from thrillers to romance to political intrigue to hopefully suit whatever mood or tastes you have. They're not in any particular order, I've watched nearly all of these and loved them. If you'd to know more about any of them, or if you'd like more drama recommendations, or if you'd like to extend the recommendations to anime and manga as well, I'd be happy to help you and do a more extensive search, as there are simply too many dramas/manga/anime I've seen and read, and far more that fall under the categories you're asking for. So if there's anything more you'd like to ask or discuss on the subject, feel free to reach out to me. :) (I'll shut up now lol here's the list):
- Healer (vigilante)
- 100 Days My Prince (historical/amnesia)
- Ruler: Master of the Mask (historical/identity switch)
- Queen In Hyun's Man (time travel)
- Moon Lovers: Scarlet Heart Ryeo (time travel)
- City Hunter (vigilante)
- The Moon That Embraces the Sun (historical/amnesia)
- Empress Ki (cross-dressing, though not throughout the whole drama)
- You're Beautiful (cross-dressing)
- Rooftop Prince (time travel)
- Sungkyungkwan Scandal (historical/cross-dressing)
- Moonlight Drawn by Clouds (historical/cross-dressing)
- Coffee Prince (cross-dressing)
- Faith (time travel)
- Nirvana in Fire (undercover/revenge - it's a cdrama but absolutely brilliant)
- Ten Miles of Peach Blossoms (cross-dressing/amneisa/undercover - also a cdrama)
- Death Note (criminal/vigilante-wannabe - jdrama)
- Hwarang (historical/undercover)
- What's Wrong with Secretary Kim? (kinda secret identity in a way, can' really explain how [spoilers/plot twists])
- Her Private Life (Does being a secretly dedicated fangirl and major fansite owner count as secret identity? XD)
- Goblin: The Great and Lonely God (supernatural/also kinda secret identity [also spoilers/plot twists])
- I Remember You/Hello Monster (criminal)
