Flashback Small Lady
Some people wouldn't call this a form, but to be complete I decided to include it. It also underlines very clearly a strong difference between Chibiusa's identity in the manga and in the anime. The presence (shown several times in several episodes) of a toddler-sized Chibiusa in many of Chibiusa's flashbacks to her time in Crystal Tokyo makes it clear that the Chibiusa of the anime is not a nine hundred and two year old girl, but rather a normally aged and normally growing girl around six years old (the reasons I place her at this age in R are detailed below). Flashback Small Lady is a very small child, one who wets the bed and is sized so that Luna P is very nearly larger than she is. Chibiusa does not always appear so young in her flashbacks, only the ones meant to signify that they happened when she was a very small girl.
Chibiusa (circa BSSMR)
In Sailormoon R, Chibiusa primarily appears as a little girl in a seifuku, aged around six years. There are a lot of reasons to place her at this age. First of all, her age is never clearly stated in the Sailormoon R anime, nor is the grade level she attends Juuban Elementary. At one point we are given a flashback of a birthday party for her in Crystal Tokyo where she looks to be the same age as she is in Sailormoon R, and there are five candles on that cake, possibly giving an indicator that she is at least five years old. From her behavior and the behavior of her classmates (two other little children in her swim class cry during a thunderstorm when their parents are late picking them up) one can only assume that she is intended to be this young, or slightly older. Six years old seems to be a good mean age to place her at in Sailormoon R. In this season she is constantly seen wearing her seifuku (which she has brought with her from the future). The summer version has a white short-sleeved shirt with a red sailor collar. The winter version has a long-sleeved blue shirt with a blue sailor collar. Both have red front bows and a short blue skirt.
Black Lady is the abominable adult form of Chibiusa that Wise Man creates through the power of the Jakokuzuishou, brainwashing, and the skewing of Chibiusa's memories. Black Lady appears to be nearly the same age as Neo Queen Serenity, who is slightly taller than she is. She has similar proportions and very slender long legs. Her hair is thin, the tails to her odango being as long and silky as Sailor Moon's as opposed to being thick and short. Her eyes are glassy and her pupils lack their largest shine (a sure sign of a villain in Sailormoon). She wears black and dark pink, has a crescent moon of the Black Moon family on her forehead, and claims that she has been reborn through the power of Wise Man to see through the lies of love and truth. She believes she has always been alone although she was always craving love and attention, and thinks she was abandoned or treated cruelly by everyone she has ever known. She calls Luna P her only friend, and the magical toy goes over to the dark side with her. As a villain, other than her unusual resonance with the Jakokuzuishou, her powers are pretty standard villain fare: teleporting, levitation, and she retains her ability to turn Luna P into useful objects, which usually then spew dark energy at her opponents.
Small Lady (circa BSSMR)
This is Chibiusa's ascended form. It is in this form that she is able to call upon the ginzuishou of the future. Small Lady wears a white dress almost identical to Princess Serenity's and has the ability to tap the crystal and levitate. Small Lady appears only very briefly when Chibiusa expresses a wish to help Neo Queen Serenity defeat the Death Phantom. The ginzuishou then emerges from Chibiusa's body, where it has been lying dormant since she touched it, way back before this whole mess began. She begs the crystal to give her the power to fight, although it may cost her her life. The crystal grants her wish and she ascends into Small Lady and helps the Neo Queen defeat the Death Phantom.
Chibiusa (circa BSSMS)
This is the first of our time conundrums featuring the time-trotting soldier of the future moon. When Chibiusa comes back from the future in Sailormoon S, she seems to have aged consideraby to when she first appeared in Sailormoon R, although only about five or six months have passed in the actual timeline. Although still a child, she is older and leggier and more self-possessed, and rather more like a girl of nine would be. Her proportions are less exaggerated than her appearance in R, and her behavior is much more developed as well. It is in this season that Chibiusa's thoughts first turn to love and she devlops a crush, as well as befriending the lonely Tomoe Hotaru, the latter of which requires great determination and sensitivity. She is no longer a tiny little girl. So where is the time conundrum? Chibiusa went back to the future for six months. Isn't it possible she stayed there for quite a bit longer, training to be a senshi, before she actually popped back up in the twentieth century? Well, that would be an acceptable explanation if not for the fact that in BSSM SuperS Chibiusa is in the same class with classmates she had back in BSSM R (namely Momo and Kyusuke) who are also much older than they are when they originally appear, and inline with her age in that season. Oh, BSSM anime. You are so commonly contradictory. Chibiusa's seifuku in this season is a long sleeved blue sailor blouse with a white collar with pink trim in the winter, and a short sleeved white sailor blouse with a white collar with pink trim in the summer. Both of these uniforms are paired with a short blue skirt, and the front bows are both white with pink trim.
Sailor Chibimoon is the beautiful sailor-suited warrior-in-training. She is full of bravado, although her attack "Pink Sugar Heart Attack" sometimes doesn't work. Even when this attack does work, it does little more than stun or distract the enemy (and at worst, it just really pisses them off). Her transformation "Moon Prism Power, Make Up" is rarely shown in its entirety. Generally, she just holds up her brooch and yells her henshin phase and there's a sparkle. Suddenly she's standing posed in her usual position, in full fuku. Sailor Chibimoon wields the Pink Moon Stick and transforms with the Prism Heart Brooch.
Chibiusa (circa BSSMSuperS)
Again, a year or more seems to have passed between Sailormoon S and Sailormoon SuperS, as far as Chibiusa's growth is concerned. Again, you could point to her returning to the future at the end of Sailormoon S and her subsequent reappearance as time for this aging up, but again you have to look and see Chibiusa still in school with her classmates from Sailormoon R. Who knows, really. Suffice to say that Chibiusa is now definitely more mature even than she was in Sailormoon S, and it is in this season that she really begins to grow up, thematically, from a girl into a woman. She still attends Juuban Elementary School and she still lives with Usagi's family. This Chibiusa is more mature, although she is not above having a knock-down-drag-out fight with Usagi. Chibiusa is the maiden with the beautiful dream the pegasus not only protects, but loves. He hides in her beautiful one-of-a-kind golden dream mirror, and when all other dreams are blocked to him, the light of her beautiful dream still reaches him. Her beautiful dream is to someday make friends with everyone. She is not nearly as selfish in SuperS as she appears to be in earlier seasons. Chibiusa no longer has Luna P, instead she has her own guardian, a diminutive gray kitten named Diana with a penchant for riding on Chibiusa's head. Chibiusa also gets the 'Stallion Reve' halfway through the series. This allows her to communicate with Pegasus even when she is awake. Her seifuku in this season is a white blouse with a red front bow and a blue skirt held up by wide blue suspenders. Since all of SuperS happens during the winter, we never get to see what her summer uniform might be like, but I imagine it is very similar, only with a short sleeved shirt.
Super Sailor Chibimoon
Sailor Chibimoon gets a power-up at the very beginning of the SuperS season. At this point she is no longer the sailor-suited senshi-in-training, but has actually come into her own power, as evidenced that the team can't fight without her. Super Sailor Chibimoon's fuku is much more elaborate than Sailor Chibimoon's uniform. It looks very much like Super Sailor Moon's fuku, except the skirt is trimmed in yellow and pink, the bows are a pale, semi-transparent lavender, and the collar is pink trimmed in gold. Like always, she wears her trademark pink boots in this ensemble. Super Sailor Chibimoon gets a full transformation with Sailor Moon and must perform her attack "Twinkle Yell" before Sailor Moon can attack with "Moon Gorgeous Meditation." Super Sailor Chibimoon is the soldier with the beautiful dream whom the dream pegasus protects. Chibimoon plays a major role in SuperS. Most of the series centers around her, in one way or another.
Chibiusa takes this form for only one episode while she has been cursed by Palla Palla of the Amazon Quartet. Palla Palla grants Usagi and Chibiusa's "wish" (which is actually the product of their current quarrel) and flops their ages, making Usagi elementary aged and Chibiusa 15. At first, Chibiusa loves this form. It has fufilled her dream of becoming a beautiful lady, sort of. Also, she can't wait for Elios to see her and she's desperate to know what he thinks of her beautiful new figure. However it soon becomes clear that Chibiusa can't meet Pegasus in her dream while she's cursed. He manages to find her anyway, and he explains that he can't find the light of her dream while she's an "adult." She also gets her first glimpse of Elysian while in this form. He explains that he will never be able to find her while she's cursed with a false dream, and he turns to leave. Chibiusa, in tears, runs after him and in doing so breaks the curse and turns back into a child. Then she gets her first kiss. Teen Chibiusa appears to be about the same height as Usagi, but more developed. Her hair is longer, but still thick. In this form she wears Usagi's pajamas and also her own seifuku for a while, which is sadly hilarious, considering she is bursting out of it.
Small Lady (circa BSSMSuperS)
Although appearing commonly in Chibiusa's dream sequences with Pegasus, Chibiusa only takes this form in actuality only briefly at the end of SuperS when Neherenia tosses Chibimoon from her rapidly ascending ruined temple. Sailor Moon jumps off after her rather than be separated from her. They fall (Chibiusa is unconscious) and Sailor Moon spends the majority of the time trying to wake Chibimoon back up. When she finally does, they both ascend to princess forms (that's right, Princess Serenity and Small Lady, not Neo Queen Serenity and Small Lady) and then Small Lady summons Pegasus and he comes to aid "his maiden." He catches the two of them and gives them beautiful angelic wings with which they float safely down to a walking bridge overpass. In SuperS, Small Lady is clearly considerably older and more developed than when this form first appeared in Sailormoon R. The dress itself seems slightly different as well, and slightly more fitting an older girl -- the back bow being well defined and the skirts being multiple layers, features the R dress does not seem to have.