This is the CosplayGrill Firelands Portal Tempo Mage Deck he was using 
on stream to climb from the dumpster into the high legend ranks <100.
Firelands Portal is an interesting card that’s still being tested but does seem to have a home in the slower Tempo Mage deck lists like this one. This deck has Emperor Thaurissan and Ice Block, so it’s built for the longer games than the heavy burn Mage decks.