How to send FCM Notification to a list of specific device tokens using the v1 API

There is currently no other way to send to multiple tokens besides using topics for FCM v1.

In your mentioned use case, if I'm using v1, I would probably go at something like, after selecting the winning tokens, you subscribe them to a topic like winningTokens<date_here> then send the message.

For other use cases, the best way to send to multiple devices via v1 API depends on your application. For example, the accepted answer would not be a good solution for a private chat application where another user can guess the topic name and evesdrop on the conversation by subscribing to the topic. In that scenario iterating over the device list and making multiple send calls to a single device would be better.