The only bear pattern I could ever find was Butterick 3683, sold on eBay & other similar vwebsites. It's for the 17" Build-A Bear. Includes a front buttoned shirt with peter pan collar; pants with a buttoned waist band & a nightshirt. It's basic enough to make other garments too, such as changing the collar to a mandarin type or using a back closure & making the pants more simple using a fold over waist & elastic to fit. I've done a jacket, overalls, winter long coat, etc. all from that pattern.
I can't check to see if it's still available. Internet connection is iffy where I am now & I won't be back home for another few weeks. Hope you can find the pattern.