There is a trans support org in my city that takes clothes donations.

My go to lately has been domestic violence shelters.

Find your nearest trans friend and ask if they know anyone who wants clothes

I sometimes straight up ask someone who is homeless and looks like my size if they want whichever particular item, especially if it is comfortable or will keep them warm.

Takes a bit longer but I’m sure they appreciate it more.

My local food pantry takes pretty much anything a person could find useful (backpacks, clothes, shoes, etc). Try seeing if there’s any local outreach/resource organizations in your area.