Here is the full list of all 59 Guitar Hero III: Legends of Rock achievements worth 1,000 gamerscore.
Win 500 Online Ranked matches
Complete all difficulties in Career, buy everything from the shop and complete 100 online matches
Buy everything from the store
Buy all the Guitars from the shop
Earn 5 stars on all Co-op songs for the Easy difficulty
Earn 5 stars on all Co-op songs for the Medium difficulty
Earn 5 stars on all Co-op songs on the Hard difficulty
5 Star all Co-op songs on Expert
Join Ranked Online matches and win 15 consecutive songs
Score 1,000,000 on any song in a Co-op match
Score 750,000 on a song
Complete all songs as the back-up guitar player
Complete Co-op Career
Complete all Co-op as the lead guitarist
Gold Stars 20 songs on Expert
Earn 5 stars on all songs on the Expert difficulty
Complete Through the Fire and Flames on Expert
Complete all Career difficulties
Complete Career Mode on the Expert difficulty
Host Ranked Online matches and win 15 consecutive songs
Win 15 consecutive Ranked songs online using a standard controller
Earn a 2000 note streak in a Co-op match
Score 700,000 on any song in a Co-op match
Activate Star Power 3 times on Through the Fire and Flames on Expert
Earn 5 stars on all songs on the Hard difficulty
Score 500,000 on any song in a Co-op match
Score 500,000 on a song
200k on Cult of Personality without Star Power
Earn $350,000 in career lifetime earnings
Play through a career on the Hard or Expert difficulty using a standard controller
Played through Career with Lefty Flip on and off
Earn 100,000,000 points total in Career
Earn a 150 note streak in a Ranked Online Battle mode match
Complete Career on the Hard difficulty
Earn a 1000 note streak in a Co-op match
Earn a 500 note streak in a Co-op match
100% a song in a Co-op match
Earn a 200 note streak in a Co-op match
Get an 8X multiplier in a Co-op game
Beat any song on the expert difficulty with the games sound options turned down to zero
Use the Whammy Bar on every held note on Number of the Beast
Earn 5 stars on all songs on the Medium difficulty
Hit 250,000 notes in Career
Buy all characters from the shop
Fail any song 10 times
Fail a song passed 90% completion
Refuse a boss battle
Complete Career Mode on the Medium difficulty
Earn 5 stars on all songs on the Easy difficulty
Score 250,000 on a song
Earn a 1000 note streak in Career or Quick Play
Earn a 500 note streak in Career or Quick Play
Beat one of the creators of Guitar Hero 3 at their own game
100% a song
Complete a Career on the Easy Difficulty
Buy all songs from the shop
Earn a 250 note streak in Career or Quick Play
Earn a 100 note Streak in Career or Quick Play
Complete the tutorial