I'm keeping the following list updated for a couple of years now:
1.0.0.0/24
1.1.1.0/24
1.2.3.0/24
8.6.48.0/21
8.8.8.0/24
8.35.192.0/21
8.35.200.0/21
8.34.216.0/21
8.34.208.0/21
23.236.48.0/20
23.251.128.0/19
63.161.156.0/24
63.166.17.128/25
64.9.224.0/19
64.18.0.0/20
64.233.160.0/19
64.233.171.0/24
65.167.144.64/28
65.170.13.0/28
65.171.1.144/28
66.102.0.0/20
66.102.14.0/24
66.249.64.0/19
66.249.92.0/24
66.249.86.0/23
70.32.128.0/19
72.14.192.0/18
74.125.0.0/16
89.207.224.0/21
104.154.0.0/15
104.132.0.0/14
107.167.160.0/19
107.178.192.0/18
108.59.80.0/20
108.170.192.0/18
108.177.0.0/17
130.211.0.0/16
142.250.0.0/15
144.188.128.0/24
146.148.0.0/17
162.216.148.0/22
162.222.176.0/21
172.253.0.0/16
173.194.0.0/16
173.255.112.0/20
192.158.28.0/22
193.142.125.0/28
199.192.112.0/22
199.223.232.0/21
206.160.135.240/24
207.126.144.0/20
208.21.209.0/24
209.85.128.0/17
216.239.32.0/19