Quick answer - None.
I think that it is more important for women to wait until a little older than men, they take longer to “fully” develop even though they reach 90% development earlier than men.
If she is going to though, she should start with Oxandrolone (anavar) at 5mg per day divided into 2 doses. she can up her dose after a week or two, but I would recommend a straight 6-8 week cycle or a 2 weeks on 2 weeks off (she would start her 2 weeks after each period) The AAS will mess with her period and can case androgenic sides.
My fiance and sister love taking low-dose Oxandrolone (as well as Turinabol) and the first side they notice is a sensitive clitoris, once they up the dose they start noticing other sides like a “dry voice”, etc. People say that once they notice the sides to lower the dose, but with females a lot of androgenic sides are perminant or at least stick around for awhile - so the idea is to use a effective dose for a boost but not to increase until sides are felt.
My fiance uses 5mg and has never tried more or wanted to. Another one that I never hear anyone suggest for women, but is good is Turinabol - 2.5mg-5mg per day. My fiance’s perfect (favorite) stack is 2.5mg oxandrolone and 2.5mg turinabol in the morning and 2.5mg oxandrolone in the evening.