man, how has nobody mentioned any of the more prominent ones like YURARA(rip), NONOA(rip) or oomune_tayuyu? Then there's also the bigger name ones that occasionally do ABDL(or, at the very least MDLB) ASMR like Mare Ch, Pikon or even Noel Shirogane. If you're fine with babinakus, there's Melia Bouqet ch. There's a couple smaller indies like Nana Sora Nagi, Beamori Yurumo, and tomeru_ikinone.
Then there's plenty of other JP ASMR pngtuber channels that do a lot of ABDL content, most notably 俺のASMR and White-Pink (run by the DLsite circle of the same name, whose writer is surprisingly female AFAIK)
And, finally there are a couple of channels that specifically focus on MDLB-style healing ASMR without explicitly being ABDL, such as YuuRi Channel, Saionji Mary, and Karin Necoma/Nekoha (although her videos are a coin toss between healing and aggressively sensual ASMR).
Keywords to use when searching for content are 赤ちゃんプレイ, おむつ. Other key words that aren't as reliable are おしがま, 放尿, and /おしっこ.
imo YURARA, White-Pink, and 俺のASMR are the best of the ones I listed for this specific content