Sudoku Puzzle Collections
Puzzles with 39 givens (collection of 2650 puzzles as of July 2, 2015)
Puzzles with 38 givens part 1, part 2 (collection of 2014078 puzzles as of February 24, 2015). First concatenate parts, then unzip.
Puzzles with 36+ symmetrical givens
Irreducible multiple solution pseudo-puzzles with 41 givens
Irreducible multiple solution pseudo-puzzles with 40 givens (expandable to 41-givens pseudo-puzzles not included)
Puzzles with 17 givens (Gordon Royle's list of 49158 puzzles as of July 3rd 2021)