On the 1st of every month, the World Chess Federation, FIDE, publish their updated ratings list taking into account games played in the previous month. So yesterday, on May 1st, the new list came out. Of course the top player is still World Champion. Magnus Carlsen, who has had an excellent year so far winning all his tournaments. But there are also age group leaders, country lists, top women players and every Internationally rated player. The youngest were born in 2013!
Ratings signify how well you are playing, and there are rating levels to achieve master titles.
Grand Master (GM) = 2500
International Master (IM) = 2400
FIDE Master (FM) = 2300
Candidate Master (CM) = 2200
Here's the top 10 list from the official FIDE ratings list
There is a site that records the live ratings of the top players after every game they play that is good to follow, called 2700chess. This site also has a list of upcoming events for the top players, so you can see when your favourite player will next be in action!
Here's a list of top players by age group that I made. I try to update this each month. Enjoy!