For my dose, which is calibrated for pretty standard feminization (via estradiol and cyproterone): Pattern baldness basically ceased and even reversed a bit, although the hair in that area still grows very slowly. No effect on facial hair. Minor reduction in muscle mass and arm veins. Breast growth came on slow and hasn't gone past "very small". Minor increase in lip thickness on the face, although it might be different for someone with more fat overall — I'm moderately skinny. Erectile function is less reliable and was almost totally nonexistent for a time. No effect on voice.

My skin became noticeably softer, and my hips and ass have become more pronounced due to storing fat differently.

As for psychological effects, the hormonal shift was kind of like going through puberty a second time on fast forward. I became intensely irritable for a time. But that all mellowed out after... a year and a half or so?

Unfortunately I can't speak specifically to lower doses meant to specifically cultivate androgyny, but my facial features have remained strong enough that, without makeup, passing for a cis woman is out of the question.

Nor sure I have a lot in the way of special experiences not typically listed, but I'll list the effects I can remember anyway.

As far as body/facial hair is concerned, I do think it has actually had a bit of an effect. The former seems to grow significantly slower and thinner than it did before, although obviously there's still some. All in all it seems to be in roughly the same range as my close cis female relatives. Facial hair also seems to be somewhat lighter in colour and might be growing slower, but I can't really say much for sure as I didn't have much at all even beforehand, and that which I did was basically invisible save for in a few localised areas of my face.

Muscle mass is definitely down, probably by a decent bit, but I wasn't particularly muscular to begin with and I can't really quantify the difference because I don't lift heavy things very often.

Breast-wise, the first thing I noticed (also the first thing I noticed on HRT) were my nipples, which got larger and puffier. Aside from that my breasts have definitely grown and seem to be continuing to do so (for reference I'm a little under two and a half years on HRT). They're pretty smallish (about a handful) but definitely noticeable. In shape they're pretty circular at the base and don't show a lot of influence from gravity, so my nipples are more or less in the centre.

Penis I didn't really use much before and definitely didn't try to do 'maintenance' on it as some people do, but later trying out of curiosity I found it kinda painful and stopped. I tried again more recently and that seems to no longer be the case.

Mood/mental state is kinda hard to evalute, obviously a lot also changed in my life just transitioning and in general so it's hard to know what to attribute to HRT. One of the classic HRT mood effects for example is being able to cry more easily, but I feel like that was kinda happening already before I finally got HRT. In general I definitely feel better than before, but I'm not sure I can say that's a direct effect of HRT as much as an effect of me liking the changes. I also may or may not have been dealing with a bit of an eating disorder when I started and I was mentally almost exclusively focussed on that so I feel like I kinda missed my window for observing any mental effects without too many extraneous factors.

My face has definitely changed while on HRT, seemingly a fair bit, although I kinda struggle to identify specifically what it is, so unfortunately I don't have much more to say there.

You didn't directly mention it but I figured I'd mention that in terms of fat redistribution pretty much all of the weight I've gained while on HRT seems to have gone directly into my thighs if the stretch marks are anything to go by.

Everyone else here gave great information, and also I would strongly encourage you to research this because there's lots of information out there about this. I always recommend the DIY HRT wiki. Even if you don't want to diy, it gives a great overview of the different drugs that get used, what a reasonable dosage is, and other stuff like that. But since you're specifically talking about taking a low dose to maintain an androgynous appearance I wanted to give some thoughts about that.

So for many of us the primary things about hrt isn't really how it changes our appearance but how it makes us feel. Like I was severely depressed and hopeless before I started estrogen, and I started feeling much better within a couple of months. I didn't look any different at the time. My mood changed, my sexuality changed (like in subtle ways, not in I'm straight now ways), my senses changed, and I just felt different in ways that are hard to describe.

The other thing is that HRT isn't some scale between look like a man, androgyny, and look like a woman. If you have gone through make puberty, it is hard to look like a woman. There are many people who can take high dose hrt for years and still mostly just look androgynous, and just look younger (you will look younger!) If you want to be super androgynous, and you're not now, you'll probably have to do a lot of other stuff besides. This might include diet changes, working out, hair removal, skincare, voice training, makeup, hair stuff, and experimenting with different styles. Realistically, a lot of us need plastic surgery to pass completely, though maybe androgyny is easier.

Also, I'm not sure there is such a thing as low dose hrt. Hrt involves a bunch of different drugs. Estrogen is usually one component, but there are half a dozen or more different ways to take it. This is why you should look at the wiki! If you just take a small amount of estrogen with no androgen blocker, my guess it that will do nothing except a little bit of breast development. Btw you're almost guaranteed to get breast development, there are some enbies who try to avoid this with various drugs, but I don't think they're very successful. If you take a high dose of androgen blocker, but low estrogen, you end up with no sex hormones, which has bad long term effects, but won't kill you despite what people say.

I'm not trying to convince you not to do it. Actually, I think the fact that you're seriously considering taking female hormones means that they might be right for you. I do think that you should ask yourself why you want to be androgynous, and if you would rather by an androgynous woman or an androgynous man, assuming both were an option. But either way, it's great that you're exploring what will make you happy, and feel free to ask more questions if you have them. Good luck!

Here's an informed consent page from Leeds NHS it should summarise changes someone may expect from taking estradiol for an extended period in a way you can understand.