if you don’t need nvidia, just get a cheap t470 board.

you can see which of the below have a tpm at thinkpads.org with some finegling

images for some parts seem presently at https://download.lenovo.com/Images/Parts/[model]/[model]_[idx].jpg where [idx] is A, B, C, … . many don’t have official part photos.

it looks like boards without nvidia have three large prominent empty chip footprints that are filled on boards with nvidia. the below are mostly listed as having nvidia. the numbers in the gaps have intel graphics and are also purportedly compatible.

01HX640

01HX641

01HX642

01HX643

01LV687 01HX692 officially listed for tp25

01LV688 01HX693 officially listed for tp25

01LV689 01HX694 officially listed for tp25

01LV690 01HX695 officially listed for tp25

T480 boards start with 01YR and 01YU