D&D 5E - Twin spell, what are some good spell choices?

Any spell that targets a single creature.

Honestly, I don't see how you can go wrong here. You're getting more bang for your slot, no matter what -- go crazy.

The limitation minimizes the possibility of exploitation, so if that's what you're looking for, I think you'll be disappointed. The feature is as powerful as it was intended to be, no more, no less.

ncG1vNJzZmivp6x7prrWqKmlnF6kv6h706GpnpmUqHy1w8inZKyolaG5bsPHmqtmmaKaerS7zJ5koKefmXq0vMSlo2abmKS2pLHSZ2tpbGlnhHA%3D