Edit on 15/08/2025: updated to add details on male leads in Western opera.
Takarazuka:
See here for my beginner's guide to Takarazuka
The official Takarazuka channel on Youtube has lots of well-shot performance clips to check out, and there are even more if you know where to search
Cantonese opera:
For a taste of how deliciously dramatic Cantonese opera can get, check out this short clip of a scene from The Butterfly Lovers, in which the two main characters (played by Joyce Koi/ 蓋鳴暉 and Ng Mei Ying/ 吳美英) struggle to come to terms with the female lead being forced into an arranged marriage
See here for my post on Yam Kim Fai (任劍輝) and Pak Suet Sin (白雪仙), the aforementioned "iconic pair" who dominated the Cantonese opera world
Many Cantonese opera films can be watched in full, in pretty decent quality, on Youtube, and English translations for much of the core repertory for Cantonese opera can be found with a quick Googling. For example, Yam-Pak's Legend of the Purple Hairpin (紫釵記) can be watched here, together with the English translation of the script here.
You can also take a look at my other posts on Cantonese opera here!
Yue opera:
Click here for a clip of Chen Lijun performing a modernised arrangement of a song from the hit Yue opera adaptation New Dragon Gate Inn (新龍門客棧). Basically can be described as "Yue opera and wuxia meet idol aesthetics"
For something more substantial, watch this pro-shot excerpt of the ending of Dream of the Red Chambers, which fuses traditional singing with modern staging. Alternatively, there are plenty of bootlegs of full shows on Youtube, so take your pick!
Trousers roles in Western opera:
Please also check out the "mezzosexual" tag :)
There are definitely some notable cases where the male lead is a trousers role, such as in Der Rosenkavalier, I Capuleti e i Montecchi (a.k.a. Romeo and Juliet), and Orlando Furioso. Also, as @siridealphosphorus kindly pointed out, it's much more common in Baroque operas, such as in Alcina, Ariodante, Giulio Cesare, Serse, and Orfeo ed Euridice.
I highly recommend the queer opera blog Queer Lorgnette, which reviews opera productions with humour, wit, and a distinctly queer and feminist eye
Korean musicals:
See here for my video on Korean musicals, which includes clips from several shows with genderblind casting
