Regarding your question, I'm afraid there is currently no filter for transitions.
You could go this way: first choose the transition effect that should prevail, and click "Apply to All". After that, you'll need to replace it manually for certain slides - still more time-consuming than with a filter, but speeds up your work anyway.

Meanwhile, I'll forward your request to the developers. There's a filter for Animation effects already, so I believe it's absolutely possible to make a similar one for transitions.

First let me say that I'm really impressed with the program, it's very intuitive and easy to use, yet still has a lot of options, and quite a number of beautiful transitions which I've not seen anywhere else, which brings me to my question.

Is there a way to disable certain transitions from being used when I select random transitions for all slides? I couldn't find that option, so it seems I have the choice to either:

a. Have random transitions picked from the complete list of 100 (or so) transitions, or

b. Manually select the transition type for each individual frame

As I typically make slideshows having 800-1500 frames (split into 20-30 individual projects), that's a lot of extra work if I have to pick a transition type for every single frame, vs just randomizing - though ideally I suppose that's the most artistic way to go about it if you're going all professional and such.

Aaron