Here is the full list of all 25 Disney Sing It: High School Musical 3 achievements worth 1,000 gamerscore.
Complete 100 songs.
Complete every song in the tracklist in Duet mode
Score over 1,000,000 in a duet.
Score over 750,000 on any song in Duet mode.
Score over 750,000 on any song in Versus mode
Complete a song in Duet mode.
Perform a gig with 2 players.
Complete a song in Versus mode.
Complete a song in Team Play mode.
Hit 75% of the notes of any song in You're On Your Own mode.
Complete 50 songs.
Complete all the lessons in Sing It Pro.
Perform a solo gig.
Hit a X4 multiplier.
Complete every song in the tracklist in Solo mode.
Complete all High School Musical 3 songs.
Score over 750,000 on 20 songs.
Score over 500,000 on 20 songs.
Complete all High School Musical 2 songs.
Score over 750,000 on 10 songs.
Complete all High School Musical songs.
Score over 1,000,000 on any song in Solo mode.
Score over 750,000 on any song in Solo mode.
Get the top score on any song.
Complete a song in You're On Your Own mode.