Please Recommend Highly Efficient Floor Standing Non-Horn Speaker Suggestions

So far is seems that you have a contemporary 75 watt MC275 VI tube amp with no mention of room size/layout/listening habits/budget.

More info would be helpful for informed feedback.

Also, are you not interested in horn "based" speakers at all?

DeKay

@OP

You may consider , speakers with AMT  tweeter.

I think AMT tweeter is a bit like an harmonica.  It may pair well with tube gear

Audiovector has AMT tweeter.

You might like the Wolf von Langa SON. Cutting edge field coil drivers, dipole presentation, happy with 18 watts. Sounds alive.

Here’s a nice review: HFA - Wolf von Langa SON

What, no love for Tekton? ;-)

A high quality speaker using the excellent Beyma AMT Tweeter-Midrange with a wave guide, midBass and powered Low  Bass below 90 Hz 

Spatial Audio technologies X3, X5 Loudspeakers  and very fair priced between $7 and $9k.