let’s keep the list to the brands that are worth buying, none of the cheap stuff that’s suspect.
lots of known names, but perhaps we’ll learn about others we weren’t aware of!
edit - you can include hybrids and combo’s with a DAC as well.
edit 2 - guess I will throw in a couple I know:
Little Dot, which I believe you have to buy off of Ebay
Schiit has a couple too, the Vali and the Valhalla.
These are all on my personal radar, there’s sooo many to be had from so many boutique manufacturers.
https://www.decware.com/newsite/CSP3.html
https://quicksilveraudio.com/products/headphone-amplifier/
https://www.primaluna-usa.com/primaluna-evo-400-tube-power-amplifier
https://www.moon-audio.com/dragon-inspire-iha-1-tube-headphone-amp.html (Dennis Had)
https://www.toraudio.com/main.html?v=6#
MapleTree Audio
https://hollowstate.netfirms.com/
Woo audio
ZMF Pendant and Mogwai
https://www.zmfheadphones.com/ampsanddacs/
It’s good to keep records like this for quick reference.
La Figaro 339 shows up on Drop occasionally. I think it’s designed by the same person who designed the Dark Voice, but it’s not the same company. Not sure, but I like it a lot:
don’t need pictures guys…just refer to the name and their website please. 
Off the top of my head since I’ve looked at them recently and not mentioned
Donald North Audio - http://www.dnaudio.com/
ZMF has the Pendant, though I believe it’s made by Amp and Sound
Zampotech makes the SW51 and Bachelor - http://www.z-ampo.tech/
linear tube audio https://www.lineartubeaudio.com/ - though they are arguably Hybrids
Glen OTL - though the only way I know to get one is to message him on head-fi
Eddie Current - https://eddiecurrent.com/
People say they aren’t hybrids? It sounds like a hybrid
Are we listing strictly tube amps or can they be hybrids?
Darkvoice 336se
Xduoo (multiple models)
you can mention hybrids.
I don’t remember if this is a tube or hybrid and apparently Monoprice is having a sale since I just went here to post this.
Liquid Platinum
https://www.monoprice.com/product?p_id=33305&gclid=Cj0KCQiAkePyBRCEARIsAMy5SctrUObG7kvbSnIHEDtML54kl5h_CXsnVdOjuRAt3g7lsh87YmCB3LcaAurXEALw_wcB
Didn’t know this company existed until today. No idea if the tube amps are actually good or not.
https://www.doukaudio.com/
I’ve had extremely positive results with both Line Magnetic and Musical Paradise.
They are inexpensive but fun. Not what this thread is for. They do NOT compare to the quality or sound of any of these other amps. I own 2 (NoBSOUND, same co) and use them often, it’s just a whole different level and scale of sound though.
Can we include tube dac/amp combos?
yup. you sure can
Man, I’d love to audition a Cayin.