The six-compartment Minimalist Box will easily hold a couple dozen flies - more than you would need for a day on the stream. At 3 3/8" x 2 1/4" x 7/8" they will conveniently fit in any pocket.
The Minimalist Box also makes reasonable lure box if you carry only a few lures with you and if they are not too large. If you mostly fish the micro spoons one small box may be all you need. The dividers are removable, so it is easy to carry a few plugs as well.
They are indeed minimalist, but if you carry on a few lures, one or two of them may be all you need. And for just $2 each, there's no reason NOT to have a couple.
Flies and lures not included.