In order to get list of vendors perform API call to standard graphql endpoint.

Example:

{
  vendorList {
    vendorId,
    vendorName,
    vendorAttn,
    email,
    telephone,
    fax,
    streetFull,
    street1,
    street2,
    city,
    zip,
    countryId,
    regionId,
    region,
    regionCode,
    billingUseShipping,
    billingTelephone,
    billingFax,
    billingStreetFull,
    billingStreet1,
    billingStreet2,
    billingCity,
    billingZip,
    billingCountryId,
    billingRegionId,
    billingRegion,
    billingRegionCode,
    status,
    carrierCode,
    urlKey,
    createdAt,
    vacationMode,
    vacationEnd,
    vacationMessage,
    accountType,
    isFeatured,
    ratingSummary
  }
}

RESPONSE

{
  "data": {
    "vendorList": [
      {
        "vendorId": "1",
        "vendorName": "vendor1",
        "vendorAttn": "",
        "email": "wtsergo.test+v1@gmail.com",
        "telephone": "4025555555",
        "fax": null,
        "streetFull": "1234 Test",
        "street1": "1234 Test",
        "street2": "",
        "city": "los angeles",
        "zip": "90210",
        "countryId": "US",
        "regionId": "12",
        "region": null,
        "regionCode": "CA",
        "billingUseShipping": "1",
        "billingTelephone": "4025555555",
        "billingFax": null,
        "billingStreetFull": "",
        "billingStreet1": "",
        "billingStreet2": "",
        "billingCity": "",
        "billingZip": null,
        "billingCountryId": "",
        "billingRegionId": null,
        "billingRegion": null,
        "billingRegionCode": null,
        "status": "A",
        "carrierCode": "flatrate",
        "urlKey": "vendor1",
        "createdAt": "2021-01-05 20:09:54",
        "vacationMode": "0",
        "vacationEnd": null,
        "vacationMessage": null,
        "accountType": null,
        "isFeatured": "0",
        "ratingSummary": "0.00 (0)"
      },
      {
        "vendorId": "2",
        "vendorName": "vendor2",
        "vendorAttn": "",
        "email": "wtsergo.test+v2@gmail.com",
        "telephone": "4025555555",
        "fax": null,
        "streetFull": "14 elmwood st ne",
        "street1": "14 elmwood st ne",
        "street2": "",
        "city": "rome",
        "zip": "30161",
        "countryId": "US",
        "regionId": "19",
        "region": null,
        "regionCode": "GA",
        "billingUseShipping": "1",
        "billingTelephone": "4025555555",
        "billingFax": null,
        "billingStreetFull": "",
        "billingStreet1": "",
        "billingStreet2": "",
        "billingCity": "",
        "billingZip": null,
        "billingCountryId": "",
        "billingRegionId": null,
        "billingRegion": null,
        "billingRegionCode": null,
        "status": "A",
        "carrierCode": "flatrate",
        "urlKey": "vendor2",
        "createdAt": "2021-01-05 20:09:54",
        "vacationMode": "0",
        "vacationEnd": null,
        "vacationMessage": null,
        "accountType": null,
        "isFeatured": null,
        "ratingSummary": "0.00 (0)"
      },
      {
        "vendorId": "3",
        "vendorName": "vendor3",
        "vendorAttn": "",
        "email": "wtsergo.test+v3@gmail.com",
        "telephone": "4025555555",
        "fax": null,
        "streetFull": "Bride Path",
        "street1": "Bride Path",
        "street2": "",
        "city": "Mantoloking",
        "zip": "44025",
        "countryId": "US",
        "regionId": "47",
        "region": null,
        "regionCode": "OH",
        "billingUseShipping": "1",
        "billingTelephone": "4025555555",
        "billingFax": null,
        "billingStreetFull": "",
        "billingStreet1": "",
        "billingStreet2": "",
        "billingCity": "",
        "billingZip": null,
        "billingCountryId": "",
        "billingRegionId": null,
        "billingRegion": null,
        "billingRegionCode": null,
        "status": "A",
        "carrierCode": "flatrate",
        "urlKey": null,
        "createdAt": "2021-02-16 07:47:41",
        "vacationMode": "0",
        "vacationEnd": null,
        "vacationMessage": null,
        "accountType": null,
        "isFeatured": "0",
        "ratingSummary": "0.00 (0)"
      }
    ]
  }
}