Telegram search engines
https://github.com/bellingcat/telegram-phone-number-checker
To find these search engines, google for “telegram search engine”, optionally with specific domain like “github.com”, “reddit.com”, “medium.com”.
Available search engines:
https://www.telegramdb.org
https://xtea.io/ts_en.html
https://groupda.com/tgme/
https://telemetryapp.io
https://cse.google.com/cse?q=+&cx=006368593537057042503:efxu7xprihg (Telegago)
https://lyzem.com/
https://tgstat.com/en/search
https://tgdev.io/tme/
https://sssoou.com
https://teleteg.com
https://lyzem.com/
https://intelx.io/tools?tab=telegram
https://kribrum.io/
https://telemetr.me/all_posts/
https://cse.google.com/cse?cx=006368593537057042503%3Aig4r3rz35qi#gsc.tab=0 (Commentogram)
https://www.telegram-groups.com/
https://telegramchannels.me/
https://tlgrm.ru/channels/
Available telegram search engine bots:
https://t.me/tgdb_bot
https://ttttt.me/SearcheeBot
https://t.me/teletegbot
https://t.me/ScadsBot
Telegram related resources:
https://taiha.dev/technology/telegram-search-engines/
https://github.com/ItIsMeCall911/Awesome-Telegram-OSINT
https://medium.com/@ibederov_en/telegram-search-engines-fc8d9c1cc1a6
https://medium.com/@teletegofficial/how-to-search-telegram-groups-and-channels-a-comprehensive-guide-b0dfc3898d35
https://www.quora.com/How-do-I-find-Telegram-groups-channels-by-keywords-and-tags-Most-of-the-time-many-channels-are-not-shown-in-search
You can directly use Google as telegram search engine, like indexed part of Telegram itself <site:t.me>, and on external aggregators, for example <site:tgstat.ru> or <site:telemetr.me>