When making a game ages ago I spent a long time trying to research good screen transitions I could use without finding any that really suited the style I was looking for. Since then I have been obsessed that whenever I am watching a movie or playing a game and I see a unique transition I add it to my catalogue of room transitions. I have made them available here for you in the hopes that it can help inspire any projects you are working on.
If you have any ideas for transitions I can add do contact me so I can program them up and add them.
Lots of people seem to know these as PowerPoint transitions.
These are all programmed in GameMaker where they are transitions between rooms.