I bought this battery replacement for my OnePlus 5T and it so far seems way better than the iFixit version : r/Oneplus5T
New Replacement Battery BLP637 For OnePlus 5 5T A5000 1+5 Five 3300mAh | eBay
G-TONG Mobile Battery For OnePlus One Plus 5T 1+5T BLP637 Price in India - Buy G-TONG Mobile Battery For OnePlus One Plus 5T 1+5T BLP637 online at Flipkart.com