This past year, I believe the Pride collection merch first made an appearance in May. So you can expect some new items to be released then. There's always new tshirt designs, water bottle, usually a small backpack, mickey ears, a rainbow Mickey plushie, sunglasses, and some other items. Some of the rainbow collection can still be found on shopdisney.com so you can look there to see if there's anything left that you'd like to buy in advance. Though once they release the new collection, they generally do a limited time thing where a portion of the proceeds are donated to GLSEN and other organizations focused on LGBTQ youth, so I choose to buy in June while that is going on.