TransitionLink is a Gatsby plugin designed to simplify the process of adding page transitions in web development, addressing the challenge of implementing aesthetically pleasing transitions between pages. Created by Tyler, the plugin allows developers to declare page transitions using props on a Link component, offering flexibility by supporting both declarative and imperative animation libraries like react-pose, react-spring, GSAP, and anime.js. TransitionLink enables customization of timing, state, and trigger functions for entering and exiting pages, providing developers with the tools to create unique, tailored transitions for their projects. Additionally, Tyler developed AniLink, a wrapper around TransitionLink, which provides default transitions like paintDrip, swipe, cover, and fade, though he encourages developers to create their own. Optional components like TransitionState and TransitionPortal further enhance the plugin's capabilities by managing transition status and positioning animation elements above pages. Tyler expresses enthusiasm for the potential creative applications of TransitionLink within the Gatsby community.