Mono red goblins is 100% competitive in the modern format, which isn't really that expensive compared to most modern lists in the format, goblins is performing better now then it has in the past.
Since it is a mono red deck and I want to keep the cost down, I am running 19 mountains. That's it, 19. You can upgrade to fetches eventually which will help with deck thinning, getting you all your goblins quicker, but to keep it simple, 19 mountains.
The strategy is pretty straight forward, play the goblins swing them sideways and win. But to go into detail, the turn one play usually is ideal to have a Goblin Guide swing for 2 until you build your board up and kick a Bushwhacker or a Mogg Fanatic taking out a Birds of Paradise, Vault Skirge or Eldrazi Mimic until you build up your field with tokens from the Mogg War Marshall and kick a bushwhacker and overwhelm your opponent. Or playing late game and having a Chieftain buff all your goblins, then building up the board enough for one of your Piledrivers to swing for a ridiculous amount of damage.
Oh damn they blocked two of your creatures, just scraping through on 5 life, too easy just throw a Goblin Grenade at their head, I cannot believe how many times I have snatched games from playing a cheeky Goblin Grenade during my 2nd main phase after a massive attack.
