OK, here's what I've managed to get from this thread as a list. This includes things I was able to locate info on which were full RPGs confirmed with a 2015 release date. It doesn't include settings or supplements, or things where I couldn't find a confirmed release date. It also doesn't include the posts I couldn't understand.
Apocalypse Prevention, Inc. 2nd Ed (Third Eye Games)
Barbarians of Lemuria: Mythic Edition (Filigree Forge)
Chill 3rd Edition (Matthew McFarland)
Cypher System Corebook (Monte Cook Games)
Delta Green: The Roleplaying Games (Arc Dream Publishing)
Deluxe Tunnels & Trolls (Flying Buffalo)
Deluxe V20 Dark Ages (White Wolf/Onyx Path)
DUST Adventures (Modiphius Entertainment)
Deluxe Exalted 3rd Edition (White Wolf/Onyx Path)
Fantasy AGE (Green Ronin)
Feng Shui 2 (Atlas Games)
Five Moons RPG (Sean K Reynolds)
Fragged Empire (Wade Dyer)
Infinity RPG (Modiphius Entertainment)
Iron Kingdoms Unleashed (Privateer Press)
Mage: The Ascension 20th Anniversary Edition (White Wolf/Onyx Path)
Mage: The Awakening Second Edition (White Wolf/Onyx Path)
Modos RPG
Mouse Guard 2nd Edition (Archaia Entertainment)
Mutant Chronicles 3rd Edition (Modiphius Entertainment)
Paranoia (Mongoose Publishing)
Red Aegis (Vorpal Games)
Robert E. Howard’s CONAN Adventures In An Age Undreamed Of (Modiphius Entertainment)
Shadows of the Demon Lord (Schwalb Entertainment)
Shadows Over Sol (Tab Creations)
Shotguns and Sorcery (Outland Entertainment)
Simple System Table-Top Roleplaying Game System (Dashing Inventor Games)
Star Wars Force & Destiny (FFG)
TimeWatch (Pelgrane Press)
Unified Rolemaster (ICE)
Urban Shasows RPG (Andrew Medeiros)
ZWEIHANDER Grimdark Edition (Grim & Perilous Studios)
That amounts to over 30 upcoming RPGs in 2015. Feel free to correct any errors! I'll post the poll a bit later.