This will allow you generate a filter list based on live registry data.

You can also use a regular 'whois' client against filtergen.dan.me.uk to get the same output.
For example, on a UNIX-based operating system such as FreeBSD:

whois -h filtergen.dan.me.uk -- "-6 -RIPE -t cisco -f example -upto 48 AS57672

Note: to remove comments, append " | grep -v ^%" to the command.

%
% Filter List Generator
% Copyright(c) 2024, Daniel Austin MBCS
%
% usage:
%   [-D] [-6] [-RIPE | -RADB | -APNIC] [-f filtername -t filtertype [-upto N]] as-set
%
% -D for DEBUG mode (shows working calculations)
% -6 for IPv6 filter generation
% -RIPE for whois.ripe.net lookups
% -RADB for whois.radb.net lookups
% -APNIC for whois.apnic.net lookups
% -f will generate a cisco-style filterlist called 'filtername' (use -t filtertype as follows)
%      cisco (default)
%      iox-xr
%      juniper (basic support)
%      force10
%      mikrotik
% Additionally, if using -f/-t you may specify -upto N where N is the prefix size to permit up-to
%
% Using whois.radb.net for lookups
% Generating filter list for 'AS8075'
102.133.0.0/16
102.133.0.0/17
102.133.128.0/17
102.211.187.0/24
102.37.0.0/16
102.37.0.0/17
102.37.128.0/17
103.11.244.0/24
103.131.148.0/24
103.131.149.0/24
103.155.245.0/24
103.158.243.0/24
103.164.236.0/23
103.164.236.0/24
103.164.237.0/24
103.180.108.0/24
103.180.109.0/24
103.249.62.0/24
103.249.63.0/24
103.58.119.0/24
103.8.80.0/24
104.146.128.0/17
104.208.0.0/13
104.234.235.0/24
104.40.0.0/13
104.47.19.0/24
108.140.0.0/14
108.161.110.0/24
108.165.60.0/24
109.176.255.0/24
111.221.100.0/22
111.221.100.0/23
111.221.100.0/24
111.221.101.0/24
111.221.102.0/23
111.221.102.0/24
111.221.103.0/24
111.221.104.0/21
111.221.104.0/22
111.221.104.0/23
111.221.104.0/24
111.221.105.0/24
111.221.106.0/23
111.221.106.0/24
111.221.107.0/24
111.221.108.0/22
111.221.108.0/23
111.221.108.0/24
111.221.109.0/24
111.221.110.0/23
111.221.110.0/24
111.221.111.0/24
111.221.112.0/20
111.221.112.0/21
111.221.112.0/22
111.221.112.0/23
111.221.112.0/24
111.221.113.0/24
111.221.114.0/23
111.221.114.0/24
111.221.115.0/24
111.221.116.0/22
111.221.116.0/23
111.221.116.0/24
111.221.117.0/24
111.221.118.0/23
111.221.118.0/24
111.221.119.0/24
111.221.120.0/21
111.221.120.0/22
111.221.120.0/23
111.221.120.0/24
111.221.121.0/24
111.221.122.0/23
111.221.122.0/24
111.221.123.0/24
111.221.124.0/22
111.221.124.0/23
111.221.124.0/24
111.221.125.0/24
111.221.126.0/23
111.221.126.0/24
111.221.127.0/24
111.221.16.0/21
111.221.24.0/22
111.221.29.0/24
111.221.30.0/23
111.221.64.0/18
111.221.64.0/19
111.221.64.0/20
111.221.64.0/21
111.221.64.0/22
111.221.64.0/23
111.221.64.0/24
111.221.65.0/24
111.221.66.0/23
111.221.66.0/24
111.221.67.0/24
111.221.68.0/22
111.221.68.0/23
111.221.68.0/24
111.221.69.0/24
111.221.70.0/23
111.221.70.0/24
111.221.71.0/24
111.221.72.0/21
111.221.72.0/22
111.221.72.0/23
111.221.72.0/24
111.221.73.0/24
111.221.74.0/23
111.221.74.0/24
111.221.75.0/24
111.221.76.0/22
111.221.76.0/23
111.221.76.0/24
111.221.77.0/24
111.221.78.0/23
111.221.78.0/24
111.221.79.0/24
111.221.80.0/20
111.221.80.0/21
111.221.80.0/22
111.221.80.0/23
111.221.80.0/24
111.221.81.0/24
111.221.82.0/23
111.221.82.0/24
111.221.83.0/24
111.221.84.0/22
111.221.84.0/23
111.221.84.0/24
111.221.85.0/24
111.221.86.0/23
111.221.86.0/24
111.221.87.0/24
111.221.88.0/21
111.221.88.0/22
111.221.88.0/23
111.221.88.0/24
111.221.89.0/24
111.221.90.0/23
111.221.90.0/24
111.221.91.0/24
111.221.92.0/22
111.221.92.0/23
111.221.92.0/24
111.221.93.0/24
111.221.94.0/23
111.221.94.0/24
111.221.95.0/24
111.221.96.0/19
111.221.96.0/20
111.221.96.0/21
111.221.96.0/22
111.221.96.0/23
111.221.96.0/24
111.221.97.0/24
111.221.98.0/23
111.221.98.0/24
111.221.99.0/24
113.197.64.0/24
113.197.65.0/24
113.197.66.0/24
113.197.67.0/24
128.94.0.0/16
129.35.19.0/24
13.104.0.0/14
13.107.14.0/24
13.64.0.0/11
130.115.248.0/22
130.115.252.0/22
131.253.1.0/24
131.253.12.0/22
131.253.128.0/17
131.253.24.0/21
131.253.32.0/20
131.253.5.0/24
131.253.6.0/24
131.253.61.0/24
131.253.62.0/23
131.253.8.0/24
132.164.0.0/16
132.245.0.0/16
134.170.0.0/16
135.130.0.0/16
135.149.0.0/16
135.56.0.0/24
135.56.4.0/24
137.116.0.0/16
137.117.0.0/16
137.135.0.0/16
137.70.152.0/24
137.70.154.0/24
138.105.0.0/16
138.128.250.0/24
138.128.251.0/24
138.239.0.0/16
138.32.108.0/24
138.91.0.0/16
141.193.248.0/24
142.0.188.0/24
142.0.189.0/24
142.147.54.0/24
142.147.61.0/24
144.203.152.0/24
144.203.153.0/24
145.219.22.0/24
145.219.23.0/24
145.219.24.0/22
145.219.28.0/22
145.46.160.0/24
145.46.161.0/24
147.140.72.0/24
147.140.73.0/24
147.145.0.0/16
147.243.0.0/16
148.7.0.0/16
149.5.186.0/24
150.171.0.0/16
150.171.0.0/24
150.171.254.0/24
151.206.0.0/16
153.98.24.0/24
155.60.224.0/24
155.60.225.0/24
155.60.226.0/24
155.60.227.0/24
155.60.228.0/24
155.60.229.0/24
155.60.230.0/24
155.60.231.0/24
155.60.232.0/24
155.60.233.0/24
155.60.234.0/24
155.60.235.0/24
155.60.236.0/24
155.60.237.0/24
155.60.238.0/24
155.60.239.0/24
155.60.240.0/24
155.60.241.0/24
155.60.242.0/24
155.60.243.0/24
155.60.244.0/24
155.60.245.0/24
155.60.246.0/24
155.60.247.0/24
155.60.248.0/24
155.60.249.0/24
155.60.250.0/24
155.60.251.0/24
155.60.252.0/24
155.60.253.0/24
155.60.254.0/24
155.60.255.0/24
155.62.0.0/16
156.20.22.0/23
157.31.0.0/16
157.55.0.0/16
157.56.0.0/16
157.95.0.0/16
158.158.0.0/16
158.23.0.0/16
159.105.18.0/24
159.128.0.0/16
161.131.217.0/24
161.195.100.0/22
161.195.155.0/24
161.195.96.0/22
161.221.0.0/24
161.221.1.0/24
161.221.2.0/24
161.221.3.0/24
161.221.4.0/24
161.69.104.0/24
162.254.245.0/24
162.254.247.0/24
163.199.84.0/23
164.75.128.0/24
167.105.0.0/16
167.162.0.0/16
167.186.0.0/16
167.21.152.0/21
167.21.32.0/21
167.220.240.0/22
167.220.240.0/23
167.220.240.0/24
167.220.241.0/24
167.220.242.0/23
167.220.242.0/24
167.220.243.0/24
167.92.211.0/24
167.92.212.0/24
168.61.0.0/16
168.62.0.0/15
169.138.0.0/16
170.114.39.0/24
170.114.47.0/24
170.114.56.0/24
170.114.57.0/24
170.165.0.0/16
170.176.205.0/24
170.22.154.0/23
170.22.156.0/23
170.39.87.0/24
170.62.37.0/24
170.88.82.0/24
170.88.83.0/24
170.88.84.0/24
170.88.85.0/24
172.128.0.0/11
172.160.0.0/11
172.200.0.0/13
172.208.0.0/13
173.241.37.0/24
176.116.123.0/24
178.255.242.0/24
185.113.189.0/24
185.115.155.0/24
185.116.168.0/24
185.116.169.0/24
185.117.183.0/24
185.117.230.0/24
185.117.95.0/24
185.135.57.0/24
185.149.54.0/24
185.154.80.0/24
185.154.81.0/24
185.154.82.0/24
185.154.83.0/24
185.187.104.0/24
185.187.105.0/24
185.195.244.0/24
185.195.245.0/24
185.209.208.0/24
185.209.209.0/24
185.211.208.0/24
185.222.140.0/22
185.236.124.0/24
185.236.221.0/24
185.242.137.0/24
185.242.139.0/24
185.36.58.0/24
185.52.203.0/24
185.76.37.0/24
188.94.190.0/24
191.232.0.0/13
192.100.104.0/21
192.100.112.0/21
192.100.120.0/21
192.100.128.0/22
192.102.165.0/24
192.12.20.0/24
192.131.254.0/24
192.150.134.0/24
192.150.135.0/24
192.160.194.0/24
192.197.157.0/24
192.243.86.0/24
192.243.87.0/24
192.28.24.0/24
192.28.25.0/24
192.40.76.0/24
192.40.77.0/24
192.40.78.0/24
192.40.79.0/24
192.48.225.0/24
192.71.41.0/24
192.84.159.0/24
192.84.160.0/24
192.84.161.0/24
193.134.96.0/24
193.134.98.0/24
193.149.64.0/19
193.189.114.0/23
193.221.113.0/24
193.53.155.0/24
194.180.131.0/24
194.34.228.0/24
194.41.16.0/20
194.41.22.0/24
194.44.235.0/24
194.49.206.0/24
194.50.21.0/24
195.105.26.0/24
195.105.27.0/24
195.114.140.0/24
195.8.43.0/24
195.85.113.0/24
198.180.95.0/24
198.180.97.0/24
198.185.5.0/24
198.200.130.0/24
198.206.164.0/24
198.22.19.0/24
198.22.205.0/24
198.245.174.0/24
198.47.13.0/24
198.49.8.0/24
198.51.0.0/24
198.52.0.0/24
198.8.73.0/24
198.91.39.0/24
199.0.184.0/24
199.0.185.0/24
199.103.122.0/24
199.103.90.0/23
199.189.36.0/24
199.189.37.0/24
199.189.38.0/24
199.21.128.0/24
199.233.162.0/24
199.242.32.0/20
199.242.48.0/21
199.255.253.0/24
199.30.16.0/20
199.38.175.0/24
199.60.28.0/24
199.65.243.0/24
199.65.247.0/24
199.65.251.0/24
199.65.27.0/24
199.65.29.0/24
199.65.30.0/24
199.65.31.0/24
199.65.40.0/24
199.74.210.0/24
2.58.103.0/24
20.0.0.0/11
20.135.0.0/16
20.136.0.0/17
20.143.0.0/16
20.150.0.0/15
20.152.0.0/16
20.153.0.0/16
20.157.0.0/16
20.160.0.0/12
20.184.0.0/13
20.192.0.0/10
20.196.0.0/18
20.203.0.0/17
20.33.0.0/16
20.36.0.0/14
20.37.64.0/19
20.40.0.0/13
20.45.128.0/20
20.45.64.0/20
20.45.80.0/24
20.46.144.0/20
20.46.192.0/19
20.46.32.0/19
20.46.32.0/24
20.48.0.0/12
20.64.0.0/10
20.74.128.0/17
202.12.70.0/24
202.14.244.0/24
202.22.173.0/24
202.27.147.0/24
202.89.224.0/21
202.89.224.0/22
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203.12.31.0/24
203.21.152.0/23
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203.21.153.0/24
203.23.232.0/24
203.32.10.0/23
203.32.10.0/24
203.32.11.0/24
203.32.8.0/24
203.84.134.0/24
203.84.135.0/24
204.14.180.0/22
204.140.80.0/24
204.152.140.0/23
204.152.95.0/24
204.209.219.0/24
204.231.194.0/24
204.239.54.0/24
204.79.135.0/24
204.79.179.0/24
204.79.195.0/24
204.79.252.0/24
204.95.96.0/20
205.135.211.0/24
205.135.212.0/24
205.143.44.0/24
205.143.45.0/24
206.138.168.0/21
206.191.224.0/19
206.209.107.0/24
207.174.51.0/24
207.46.0.0/19
207.46.128.0/17
207.46.36.0/22
207.46.40.0/21
207.46.48.0/20
207.46.64.0/18
207.68.128.0/18
208.103.174.0/24
208.66.228.0/24
208.68.136.0/21
208.76.45.0/24
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208.80.20.0/24
208.80.21.0/24
208.84.0.0/21
208.90.118.0/24
209.143.212.0/24
209.143.213.0/24
209.185.240.0/23
209.185.240.0/24
209.199.0.0/16
209.240.192.0/19
209.251.248.0/24
209.46.30.0/24
209.51.100.0/24
212.1.218.0/24
212.1.219.0/24
212.1.222.0/24
212.1.223.0/24
212.46.57.0/24
212.56.56.0/24
213.156.248.0/24
213.199.128.0/18
213.218.48.0/22
216.126.214.0/24
216.183.110.0/24
216.183.111.0/24
216.220.203.0/24
216.220.204.0/24
216.220.208.0/20
216.32.180.0/22
216.73.183.0/24
216.99.143.0/24
217.169.202.0/24
23.100.0.0/15
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23.103.128.0/17
23.103.160.0/20
23.103.64.0/18
23.148.120.0/24
23.96.0.0/14
4.144.0.0/12
4.160.0.0/12
4.176.0.0/12
4.192.0.0/12
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40.104.0.0/14
40.104.0.0/15
40.107.142.0/23
40.107.18.0/23
40.108.128.0/17
40.110.0.0/15
40.112.0.0/13
40.119.160.0/19
40.120.0.0/14
40.120.0.0/20
40.123.192.0/19
40.123.224.0/20
40.124.0.0/16
40.125.0.0/17
40.126.0.0/18
40.126.128.0/17
40.126.192.0/23
40.127.0.0/16
40.127.0.0/19
40.162.0.0/16
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40.170.0.0/16
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40.64.0.0/15
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40.66.166.0/24
40.67.0.0/16
40.68.0.0/14
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40.80.0.0/12
40.95.238.0/23
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40.96.0.0/13
41.223.11.0/24
45.143.224.0/24
45.143.225.0/24
45.146.100.0/22
45.66.80.0/24
45.8.43.0/24
45.82.119.0/24
46.29.242.0/24
48.192.0.0/12
48.208.0.0/13
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51.10.0.0/15
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51.4.0.0/15
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52.105.196.0/23
52.112.0.0/14
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52.136.0.0/13
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52.152.0.0/13
52.160.0.0/11
52.224.0.0/11
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52.96.0.0/12
52.96.0.0/14
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57.150.0.0/15
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57.160.0.0/12
61.202.165.0/24
62.12.56.0/24
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62.12.60.0/24
62.12.61.0/24
62.132.26.0/23
62.97.228.0/24
63.116.158.0/24
64.13.130.0/24
64.15.23.0/24
64.15.25.0/24
64.4.0.0/18
64.72.206.0/24
65.52.0.0/14
66.119.144.0/20
66.178.148.0/24
66.178.149.0/24
67.210.128.0/24
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68.154.0.0/15
68.210.0.0/15
68.218.0.0/15
68.220.0.0/15
69.52.192.0/24
69.52.193.0/24
69.52.198.0/24
69.52.199.0/24
69.52.204.0/24
69.59.17.0/24
69.84.180.0/24
69.84.181.0/24
70.152.0.0/15
70.156.0.0/15
70.37.0.0/17
70.37.128.0/18
72.144.0.0/14
72.152.0.0/14
72.18.78.0/24
74.160.0.0/14
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74.224.0.0/14
74.234.0.0/15
74.240.0.0/14
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74.80.229.0/24
80.64.222.0/24
81.22.128.0/24
91.202.103.0/24
91.203.230.0/24
91.216.184.0/24
91.225.248.0/24
91.242.222.0/24
91.245.215.0/24
92.118.22.0/24
92.118.23.0/24
94.143.105.0/24
94.143.106.0/24
94.143.107.0/24
94.143.108.0/24
94.245.64.0/18
95.128.193.0/24
98.64.0.0/14
98.70.0.0/15
% end of filter list for 'AS8075' (712 prefixes found) 
% took 0.46 secs for query (0.22 secs of connection time)
% used 1 connections -- 2137 lines of whois data parsed