(My list is heavy on Achronim becasue Rishonim’s views are often in dispute. For example R’ Moshe held the Rambam views abortion as murder; the Achiezer and Minchas chinuch argue, but according to some yo ucan add the Rambam to the bove list. Similarly the Achiezer brings from a Ran in chullin that it isnt murder, though again others dispute this.
also, as mentioned in previous threads; not murder does not equal muttar. This should be obvious but this point often gets lost so it is worth repeating. One poster mistakenly suggested if it isnt murder it should be celebrated. A contention that is utterly baffling )