There are 2 repositories under telegram-theme-dark topic.
Minimalistic dark theme for Telegram clients (Windows, Linux, macOS, iOS, Android)
😍 A cool dark theme for Telegram Desktop
Black theme with blue accent only for Telegram For Android
A collection of my own telegram themes for desktop!
Telegram theme that looks like the WhatsApp Dark theme.
An "Acid Lime and Dark" theme for Telegram Android.