D3 Publisher released the official LINE sticker set of the Idol Death Game TV PlayStation Vita game. You can get the sticker set for 50 coins or 120 Yen (available only in selected regions). Like any other LINE sticker set this one also comes with 40 different stickers based on the idol PS Vita survival game. You can get it from here: https://store.line.me/stickershop/product/1403870
It should be noted that you can get the digital version of the game with special discount from the Japan PSN until March 31, 2017. The original price is 6000 Yen + tax BUT now you can get it for 4536 Yen (with tax). If you are a PS Plus member you can get it with 60% OFF which means for 2592 Yen (with tax).