group-price
There are 2 repositories under group-price topic.
MagePsycho/Magento2-Regular-Special-Tier-Price-Importer
Fastest Price(Regular, Cost, Special, Tier & Customer Group Price) Importer/Exporter Extension for Magento 2
MagePsycho/magento2-regular-special-tier-price-importer-sample-files
Sample CSV Files for Magento 2 Price(Regular, Special & Tier Price) Import / Export Extension