Hi, I detected that the following effects are keyframable: Alpha gradient Alpha Operations Contrast Hue shift Denoiser Sharpen Position and Zoom Transform Adding the suffix (keyframable) to the effect name is very useful to distinguish from other effects since this effects are usable for animation.
Thanks for report and sorry for huge answer delay. Since then Kdenlive & MLT evolved a lot. Now almost all effects are keyframable, so no more need to state it :)