You may occasionally find user-submitted arrangements on IMSLP, but these are frequently taken down if they violate the 1974 copyright held by the original publishers. Verified Sources for Libertango Sheet Music
: Because Libertango was first published in 1974, it is generally not in the public domain in the United States or many other jurisdictions where the "Life + 70 years" rule applies (Piazzolla passed away in 1992). Search Tips : libertango piazzolla imslp
Many modern musicians have re-engraved Libertango using software like LilyPond or MuseScore. These are often cleaner than the original manuscript and are uploaded by users who simply want to share their work. libertango piazzolla imslp