3 Most well known, should get you started:
1 -
Nova Launcher - Very nice, fast and stable. Constant updates and has a Free a Prime Available.
NOVA LINK
2 -
Apex Launcher - Again, fast and stable, has a Tablet UI mode which may be of use to some (Free and Paid Available)
APEX LINK
3 -
ADW Launcher - Fast, Stable (don't know much about ADW) (Free and Paid Available)
ADW LINK
All 3 of these accept Themes, and Apex/Nova often come with the same themes, so in play Store you'll See: Theme Name Apex/Nova
Sometimes ADW is usable too.
Less popular (perhaps still well known):
1 -
Lightning Launcher - Very nice launcher, a little different to the rest with some nice features. (Not used myself)
LIGHTNING LINK
2 -
GoLauncher - VERY WELL KNOWN (MOST DOWNLOADED LAUNCHER), Been around for quite some time, however I heard security issues with GoLauncher and other Go Products.
GO LAUNCHER LINK
3 -
Holo Launcher - Don't know anything about it just know it exists.
HOLO LINK
Hope this helps.