I think I know all but one:

• Browns at the top left: People of color
• Multicolor at the top center: Pride flag
• Pink at the top right: Women in general? No idea tbh
• White, blue and soft punk at bottom left: Trans flag
• Purples at bottom right: Feminist movement

Its a nice shirt with a good message and good intentions, but I would really want these things to include references to regular people too, not just almost exclusively sexual related minorities; I mean, the message is one of unity and is not related to minorities specifically, if you want to talk about inclusion these messages would get a deeper effect in society if it really included references to bigger, broader groups of people, like men, or to other minorities usually not included in these contexts like people with disabilities, for example