I don't think I've ever seen any of the stickers from the telegram company actually used in a chat.
I've seen lots of stickers that people have had drawn, though, sometimes even used by the people who commissioned them.
Telegram puts out a lot of packs, but they're made by different artists. You may be using their packs without realizing it. Everything on the Trending tab is theirs, and it changes frequently. Here are three packs with bats that I use, all commissioned by the Telegram team.
https://tlgrm.eu/stickers/MrBat https://tlgrm.eu/stickers/BattyBat https://tlgrm.eu/stickers/FangBat