I spent way too much time and money buying toys for the first few months and DD did not care for many of them. But here are some good choices
Playmat and usually they come with 4-10 separate toys
Chimey rattles to hang from carseat handles, etc
Wubbanub paci (lifesaver in our house)
Lamaze toys like Freddie the Firefly or Mortimer the Moose, etc.
Cloth books with 3D elements
A lovie or taggie blanket
A couple of teethers, Sophie being the perennial favorite (DD was not a huge fan though).
Some bath toys like ducks, stacking cups, Boon water toys, etc.