Are you saying that you want to know whether there are commonly accepted definitions that already exist? Or are you asking for fun add-ons?
If you want to know whether there are common definitions, there are:
DL (Diaper Lover) refers to someone with diaper fetishism, i.e. a sexual attraction to, or for interactions with/involving, a diaper. See https://en.wikipedia.org/wiki/Diaper_fetishism. The primary interest is the diapers themselves and acts involving their use. Sometimes it's just an interest, i.e. a general curiosity, or a kink, i.e. sexual satisfaction is heightened when they are involved, and other times it's a true fetish, i.e. where their presence is required to achieve orgasm. There's a real spectrum.
AB (Adult Baby) refers to role players where they like to be regressed to, and act like, someone much younger. See https://en.wikipedia.org/wiki/Paraphilic_infantilism. Some like to play true babies, i.e. are unable to care for themselves at all, while others enjoy playing older babies, toddlers, or little kids. While diapers or pullups may be involved, the focus is on the head space and acting younger, so age play.
Some argue that ABDL was very carefully chosen so it could be AB, BD, *and* DL. This means that there is *B*ondage and *D*isipline, i.e. BDSM, inherent to the umbrella term. While some DLs who engage in those activities with others do so as complete equals, when more than one person is involved, often times there is some form of power exchange where one has more power than the other, such as acting in a more nurturing role, like a babysitter or parent. Other times the power exchange may involve the diapers just a form of extra bondage (or for practical purposes for lengthy tie ups). They could also incorporated be for the purposes of humiliating or degrading the submissive or slave.