The Core Transitions (Seamless Transitions) category from the free AinTransitions PPro extension contains 13 subcategories and a total of 83 free transition presets for the Premiere Pro inside.
Camera - Panorama A
Displacement - Circle Shift
Fade - Blur Directional
Fade - Blur
Fade - Directional RGB
Fade - Swap Zoom
Simple - Simple
Skew - Flip
Slide Simple - Short
Spin - Simple
Split - Smooth
Elastic Swap
Zoom Mixed - Shake A
Zoom Mixed - Spin Tunnel