The "19 piece tile puzzle" is made/distributed by
Tobar. They have a solution to an old 19 piece tile puzzle (
spiders), but none of the new versions yet (bugs, lizard, fish, butterflies). See if the spiders solution contains any hints.
Also,
this image might help.
Good luck,
Skarabajo.
Edit 1: I just noticed that the spiders puzzle doesn't have pieces with all six spider colors (that is, every piece has at least one color repeated; particularly in the expert version, where no repetition would be possible), whereas the bugs puzzle seems to have several pieces with all six bugs represented (no repetition per piece). Is this the case for all 19 pieces? Either way, I doubt that the spiders puzzle solution will help you. If you take a picture of all the piece, maybe someone can write a little bit of code to find a brute-force solution.
Edit 2: I have found
the a
solution for the lizard version of this puzzle. Maybe this one will have some pattern or a hint that can help you with the bugs version.
Edit 3: I have found a
solution for the butterfly version of this puzzle. I have compared it to the lizard version above and there are no similarities in the pattern (In the comparison, I included rotations and slight translations). Either each puzzle have its own unique solution, or all puzzles have several solutions.