I'm not sure if I this is the response that you want or not. I first used the first URL that you have listed... The response from that looked like it didn't have the available coins. I then tried the below URL instead and the response does have a lot of curriencies listed on it. You can parse it by loading with JSON and looking for the fields that you want.
Also I didn't see a language posted with your question. I'm using python3 below. If you're a Linux person you can also just use curl GET from the command line. It doesn't matter the language... you just need to make a GET request to that URL and parse the response however you see fit.
To get 1 particular field you can use a line like response['data']['rates']['BTC'] to extract '0.00029200' out of the response/JSON string.
>>> r = requests.get("https://api.coinbase.com/v2/exchange-rates")
>>> response = json.loads(r.text)
>>> pprint.pprint(response)
{'data': {'currency': 'USD',
'rates': {'AED': '3.67',
'AFN': '75.22',
'ALL': '108.84',
'AMD': '487.59',
'ANG': '1.79',
'AOA': '311.37',
'ARS': '37.32',
'AUD': '1.38',
'AWG': '1.80',
'AZN': '1.70',
'BAM': '1.71',
'BAT': '9.00418244',
'BBD': '2.00',
'BCH': '0.00879160',
'BDT': '83.80',
'BGN': '1.71',
'BHD': '0.377',
'BIF': '1824',
'BMD': '1.00',
'BND': '1.58',
'BOB': '6.90',
'BRL': '3.65',
'BSD': '1.00',
'BTC': '0.00029200',
'BTN': '71.11',
'BWP': '10.41',
'BYN': '2.15',
'BYR': '21495',
'BZD': '2.02',
'CAD': '1.31',
'CDF': '1631.00',
'CHF': '0.99',
'CLF': '0.0242',
'CLP': '656',
'CNH': '6.71',
'CNY': '6.70',
'COP': '3174.95',
'CRC': '608.98',
'CUC': '1.00',
'CVE': '96.90',
'CZK': '22.50',
'DJF': '178',
'DKK': '6.52',
'DOP': '50.44',
'DZD': '118.30',
'EEK': '14.61',
'EGP': '17.68',
'ERN': '15.00',
'ETB': '28.52',
'ETC': '0.25542784',
'ETH': '0.00944599',
'EUR': '0.87',
'FJD': '2.10',
'FKP': '0.76',
'GBP': '0.76',
'GEL': '2.66',
'GGP': '0.76',
'GHS': '4.98',
'GIP': '0.76',
'GMD': '49.52',
'GNF': '9210',
'GTQ': '7.74',
'GYD': '208.55',
'HKD': '7.85',
'HNL': '24.49',
'HRK': '6.49',
'HTG': '78.37',
'HUF': '276',
'IDR': '13940.00',
'ILS': '3.63',
'IMP': '0.76',
'INR': '70.93',
'IQD': '1190.000',
'ISK': '120',
'JEP': '0.76',
'JMD': '132.72',
'JOD': '0.710',
'JPY': '109',
'KES': '100.60',
'KGS': '68.70',
'KHR': '4015.00',
'KMF': '429',
'KRW': '1114',
'KWD': '0.303',
'KYD': '0.83',
'KZT': '380.63',
'LAK': '8559.50',
'LBP': '1511.15',
'LKR': '178.40',
'LRD': '160.75',
'LSL': '13.53',
'LTC': '0.03208728',
'LTL': '3.22',
'LVL': '0.66',
'LYD': '1.385',
'MAD': '9.53',
'MDL': '17.05',
'MGA': '3465.0',
'MKD': '53.78',
'MMK': '1519.04',
'MNT': '2453.75',
'MOP': '8.08',
'MRO': '357.0',
'MTL': '0.68',
'MUR': '34.23',
'MVR': '15.49',
'MWK': '728.47',
'MXN': '19.14',
'MYR': '4.10',
'MZN': '61.87',
'NAD': '13.53',
'NGN': '361.50',
'NIO': '32.60',
'NOK': '8.43',
'NPR': '113.78',
'NZD': '1.45',
'OMR': '0.385',
'PAB': '1.00',
'PEN': '3.33',
'PGK': '3.36',
'PHP': '52.13',
'PKR': '139.30',
'PLN': '3.73',
'PYG': '6084',
'QAR': '3.64',
'RON': '4.14',
'RSD': '103.53',
'RUB': '65.47',
'RWF': '886',
'SAR': '3.75',
'SBD': '8.06',
'SCR': '13.67',
'SEK': '9.05',
'SGD': '1.35',
'SHP': '0.76',
'SLL': '8390.00',
'SOS': '582.00',
'SRD': '7.46',
'SSP': '130.26',
'STD': '21050.60',
'SVC': '8.75',
'SZL': '13.52',
'THB': '31.23',
'TJS': '9.43',
'TMT': '3.50',
'TND': '2.968',
'TOP': '2.26',
'TRY': '5.18',
'TTD': '6.77',
'TWD': '30.72',
'TZS': '2317.00',
'UAH': '27.70',
'UGX': '3670',
'USD': '1.00',
'USDC': '1.000000',
'UYU': '32.58',
'UZS': '8380.00',
'VEF': '248487.64',
'VND': '23287',
'VUV': '111',
'WST': '2.60',
'XAF': '573',
'XAG': '0',
'XAU': '0',
'XCD': '2.70',
'XDR': '1',
'XOF': '573',
'XPD': '0',
'XPF': '104',
'XPT': '0',
'YER': '250.30',
'ZAR': '13.27',
'ZEC': '0.02056344',
'ZMK': '5253.08',
'ZMW': '11.94',
'ZRX': '4.04721481',
'ZWL': '322.36'}}}
