I have been using 500GB Samsung(https://www.amazon.com/SAMSUNG-Portable-SSD-1TB-MU-PC1T0H/dp/B0874YJP92?th=1) for my Model Y.
I am about the get the Buffalo SSD 2TB for $125 (https://www.amazon.com/dp/B09XS1972J?th=1 ) for my Model X refresh. One of the Steam games took all the avail 75GB, so ...