curl --request GET \
  --url https://api.hubapi.com/crm/v3/limits/pipelines \
  --header 'Authorization: Bearer <token>'

{
  "customObjectTypes": {
    "overallUsage": 123,
    "byObjectType": [
      {
        "objectTypeId": "<string>",
        "usage": 123,
        "pluralLabel": "<string>",
        "singularLabel": "<string>"
      }
    ],
    "overallLimit": 123,
    "overallPercentage": 123
  },
  "hubspotDefinedObjectTypes": [
    {
      "objectTypeId": "<string>",
      "usage": 123,
      "percentage": 123,
      "limit": 123,
      "pluralLabel": "<string>",
      "singularLabel": "<string>"
    }
  ]
}