which tube amps have strong drive/150+ watts under 15k?

The PL's will score high in   overall value/performance/flexibility.

Also will likely  drive most of your speaker choices. I don't hear any concerns with my 89 db speakers.

The 2 ohm tap may help those with impedance dips.

Longtime Dialogue HP user.

Rogue Apollo Dark also come in at 15K and have 250 Watts per side. I think they can even hit 150 Watts in triode mode! But the older non-Dark Zeus and Apollo are also good for 225 to 250 watts (depending on version and tubes) and are very affordable on the used market; usually under 5K.

Manley Neo Classic 250 were close too, but just had a price increase to 19K this January :(

You will surely get responses about how many watts you “actually need” but I’ve always enjoyed the gains from 200+ tube watts even on my 96dB Tannoys. The difference in driver grip, authority, bass, and dynamics is astonishing.

Quicksilver V4 w/KT150s will fit the bill.

The ARC 150SE I am about to put up for sale for half that budget. If I can force myself to part with it. I have a brand new ARC Ref 80S. I love both of them and will likely keep the 150 SE. Seriously. Just half an hour ago I got my strong son to lift the 150 SE to the amp stand in place of the 80S to help me make a decision. If you look at the photos of my system you will see both amps in my system due to taking the photos at different times.