Missing views dropdown filter?

I've looked through the filters and fields and tried adding them, but I don't see a way to filter views through something like a dropdown. I would think there would be a filter similar to how you enter the data in the field on the backend, where you can enter a numeric value for the interval and select from a dropdown for the interval period. The only views filters I see are text boxes. Is this implemented and I'm just missing it, or are people just using those text boxes and expecting people to type in expected values? Thanks!