This is trained on the new Magical Girl HoloWitch costume, see here: https://holowitches.hololivepro.com/

Recommended Tokens:

holowitch, layered dress, short dress, brooch, diamond hair ornament, cleavage cutout

Recommended negative: white pupils

Since there are 6 different designs for every character (check the webpage), the resulting outfit will have some variety. You can mix your own variant by using some of these tags:

white dress/black dress, gold trim/silver trim (use gold trim in negatives), thigh boots/single thigh boot/asymmetrical legwear, aysmmetrical sleeves/long sleeves/elbow gloves/gloves, cutout above navel etc.

I also found that using the character name wearing the outfit strengthens their outfit:

houshou marine, sakamata chloe, murasaki shion, himemori luna, sakura miko, amane kanata

While Pony has not been trained with the correct character names, there is still a bias due to the dataset. If you want to combine the design of the character's costume but not the specifics of the character, use prompt editing ([himemori luna::4]) or use negatives.

Resizing the LoRA slightly worsens the accuracy (the brooch design suffers a bit), but may improve flexibility a bit. Feel free to resize if you're fine with that (e.g. with sv_fro and 0.97). I also found that the IN layer blocks are not that important.