Let's talk about all the RPGs that came into prominence between 2008 and 2014 - and especially 2012-2014 - when D&D 4E was around and proving it wasn't a particularly popular version D&D - leaving a large slice of pie on the table for people to take.
We actually have a period where D&D wasn't so prominent (while still there) - so what happened then?
I saw one tweet recently where someone said that 4e did more for the indie creative scene than 5e ever did. I think I can see why:
This is when we see OSR pick up, including
Stars Without Number (2010),
Dungeon Crawl Classics (2012), and
Beyond the Wall & Other Adventures (2013).
Eclipse Phase and
Fiasco both came out in 2009. Vincent Baker's
Apocalypse World, the basis for the Powered by the Apocalypse system, was first published in 2010.
Cortex Plus was published in 2010 (e.g., Smallville, Leverage), though due to ownership changes, it later gets repackaged as
Cortex Prime in its 2017 Kickstarter. So is Green Ronin's
Dragon AGE RPG system (2010), which will become
Fantasy AGE (2015). Luke Crane's
Mouse Guard was published in 2010.
Cubicle 7's
The One Ring Roleplaying Game was published in 2011 as was John Harper's
Lady Blackbird (2011). The PbtA-derived games of
Dungeon World (2012-2013) and
Monsterhearts (2012) are published during this time.
Then there was what feels like an eruption of games in 2013.
Fate Core came out in 2013. Monte Cook's
Numenera came out in 2013. Tweet and Heinsoo's
13th Age came out in 2013. Fantasy Flight Game's
Star Wars Roleplaying Game, which is the precursor of the Genesys System, was also published in 2013. Luke Crane and Thor Olavsrud's
Torchbearer was also published in 2013. Robin Laws also published
Hillfolk during this time (2013). Free League's
Mutant: Year Zero system debuted in 2014.
A lot of current popular game systems of the indie or non-D&D scene have their origin during this time period, with a few exceptions, such as
Blades in the Dark (2016), though it was basically a PbtA hack that became its own thing, much like
Ironsworn (2018).
Edit: Names and formatting, so it's less a block of text. Also added the games
@Manbearcat mentioned.