There are 4 repositories under mtproto-server topic.
Unofficial open source mtproto server written in golang with compatible telegram client.
MyTelegram is Telegram server side api implementation written in c#
An experimental Telegram Server implementation in Python
Community fork of MTProxy that doesn't suck
mini-telegram is an unofficial, monolithic, idiomatic implementation of MTProto (telegram) server built with Rust that compatible with all telegram clients (web, android, iOS, desktop).
The central umbrella unwalledgram repo. We need to go viral and monetized by markets type/category/facet. And f/l oss/libertarian!