Care is missing.
By far the character we have the most information about. Care is a child in the Petscop world. We are first introduced to Care when we receive a phone call in the Office. “Care left her room” might refer to Care's Room, as she is not found there.
Also in the office, we find a strange note with the letters A/B/NLM. Assuming the girl in the picture is Care, which is confirmed in Petscop 9, the NLM could stand for “nobody loves me” and the rest of the connections to Dr. Seuss and the Flower Shack would make sense. This is further supported as we know from the note in Care’s bedroom that she does not grow eyebrows.
She seems to be associated with a distinct yellow color, dubbed by some as "Care Yellow". Its color code is
Trichotillomania Theory Edit
There is a disorder called trichotillomania that can be caused by traumatic experiences in childhood. This disorder is defined as “a compulsive desire to pull out one's hair”. If you consider the fact that Care might be plucking her eyebrows, this would explain why she doesn’t appear to grow any. This theory further ties into the A/B/NLM note. If you consider the only difference between the A Care and the B Care is her hair, you could conclude that the note is showing progression of something happening to her hair. If Care has trichotillomania, she could be obsessively pulling out her own hair resulting in lowered self confidence and eventual depression. Ultimately this results in the “nobody loves me” part of the note, and we see her crying in the Flower Shack where she eventually becomes a glitchy mess.
In Petscop 6, Paul discovers that there are 4 more pets in the Pet menu. Interestingly, 3 of these Pets appear to be the person/people in the A/B/NLM note, which is supported when Paul catches Care NLM. This might invalidate the theory that the note is representing 3 different stages of Care’s disorder, but it is still uncertain. The 4th pet, however, is still unknown.