Full range speaker for rogue 90 or 100 wpc amp.

I would try an efficient floorstander or a high quality two way and add a subwoofer. Tube amps like to see a high impedance of 8 ohms or more so choose wisely. I would try tekton or zu audio in your price range.

Look at the Klipsch line of speakers. They are very efficient.
maybe a used pair of Proac speakers. Not as efficient as the Klipsch’s.
look at used speaker at your price range. .

Legacy might be what you're looking for. Good sound and dynamics. Easy to drive.

The Sonus Faber Lumina for around $2k are a great buy and look 
excellent for the money.

Interestingly when Herb Reichert reviewed the Rogue Stereo 100 he paired the amp with Harberth M30.2, KEF LS50, and Maggie .7 and liked them all...perhaps the Harbeth's best.  He never once tried a higher impedance/high sensitivity speaker.  Perhaps the peppy 100 watts obviated the need for a "traditional" tube-friendly speaker although he noted that the amp didn't seem any more powerful than his Pass XA25....in fact the Rogue seemed less alive, open, and dynamic.  It would have been interesting if he had tried an 8 ohm/90+dB speaker to compare to the rest.  

https://www.stereophile.com/content/rogue-audio-stereo-100-power-amplifier