Speaker for 300b amp?

Lii audio F 15’s mounted in an open baffle paired with three subwoofers. The combination brings the clarity and presence of open baffle sound together with the body and substance of the 300 b’s in my elekit kit TU 8900. Currently using PS vain horizon 300 bs But also, actually like the 2A3 tubes in the amp just a bit better with some music.

PS this amplifier also works nicely with my Klipsch heresy ones.

DeVore Fidelity O96’s and 300 Bs are a wonderful match .

I'd suggest Zu speakers as well.  Pretty efficient, but maybe not as efficient as their specs indicate.  I have one of those high watt resistors across the speaker terminals to tame the impedance down to ~8 ohms.  The 8 wpc of my 300B amp is plenty of power for my Soul Supremes.  Never any breakup or saturation distortion.

Second vote for Charney Audio.  I have the Maestro II with AER-BD3 drivers and they match well with my 300b Tube Audio Lab amp. A little pricey though. I’ve rolled Sophia and Western Electric tubes and there is a difference.