I still find Ripple Effect one of the most fun puzzle types to construct. I don't actually get to solve very many though. I am not able to find many online. Most of what you find online is computermade. They just seem to use a backtrack algorithm, where you get a valid solution and remove as many digits as you can while it stays unique. That just leads to a chaotic image of givens, which I don't find very appealing for these kinds of puzzles. My goal is always to have no givens or place the givens at the start and design the puzzle around it.
Rules for Ripple Effect