By amount of VRAM
Start from the memory your GPU has. Each page lists every model and the file that fits.
6 GB7 run well · 12 fit in some form8 GB8 run well · 22 fit in some form10 GB12 run well · 29 fit in some form12 GB17 run well · 37 fit in some form16 GB25 run well · 47 fit in some form20 GB32 run well · 48 fit in some form24 GB43 run well · 49 fit in some form32 GB47 run well · 49 fit in some form