GameStop and AMC logged further gains in premarket trading as the broader meme stock frenzy fizzled early on its third day, with Blackberry shares flat and Koss edging lower.Brick-and-mortar video game retailer GameStop was up 10.16% at 6:40 a.m. E.T., while movie theatre chain AMC rose 9.20%.Other so-called "meme stocks" were mixed in pre-trading. Shares of one-time popular smartphone maker BlackBerry were up just 0.58% and headphones manufacturer Koss fell 4.39% at 06:42 a.m. E.T.The meme stock craze resu ...