Numitrons are another option; they only require 5V to light the segments. They have a very strange, almost steampunk aesthetic (though Technology Connections is not a fan…) Unlike Nixies or VFDs, they emit a broad spectrum of light, so you can put any color filter you like in front of them (red, green, blue)

I made an alarm clock from some unusual Soviet 9-segment Numitrons a while ago. The code/design is in GitHub as well as a link to a video. https://github.com/74hc595/Numitron-Clock