I would like to study some opening theory on the Grand Prix Attack. What is a good website to study recent grandmaster games?
Chessgames has all the games from recent top GM tournaments.
Chess24 has live transmissions of the top tournaments.
And the Opening Tree at Chessok has opening variations with statistics and engine evaluations.
I think the Week in Chess website is the best place to find recent GM games. It is updated weekly, and the games are usually available for download in ChessBase format or PGN format by Monday evening every week. The usually gather the most important GM events and some minor events throughout the chess world.
I suggest Chess Tempo too. Here you can play a against ches GMs (Find Move training), searching games and openings. I recommend this site for chess training.