What speaker could safely be ordered without hearing it first?

Having owned a Audiostore I would ask ,what is your other equipment, room size 

and $$ budget  all 3 things count in building system synergy 

for example if you have a Sonus Faber which is a bit warmer, or Wilson 

 all tubes would be too much of a good thing in warmth.,

that’s just a example , and also what type of front end Thst too can be tubey warm sound if you had say a Lampizator.

Avantgarde

I purchased my Theil 3.7s without hearing them first but had 2.4s prior so I was familiar with the sound.  Very happy with my decision.  Before I purchased the 2.4s I did some serious speaker shopping and listening however.  I was surprised at the differences between some of the reviews, what I expected to hear and some of what I heard.  Ideally, I would want to audition them in my listening room but there are a few brands that I would have confidence in like Wilson, Magico and Joseph Audio.  

That’s easy. A Martin Logan 👍

+2 for the Dutch & Dutch 8C's. 

They are the most beguiling speakers I've ever heard. I purchased them without hearing them first and consider them to be my endgame speakers.  

These monitors throw a cardioid dispersion pattern, which help eliminate first wave reflections and have onboard DSP to balance out room modes. They go down to 17hz (-3Db) in my room and are incredibly detailed, minus the listen fatigue that usually accompanies high resolution presentations.  

If that weren't enough the designers are working on soon to be released integration with BACCH (cross talk cancellation software plug-in) that does what 3D glasses do for your eyes will do for your ears. This is truly revolutionary technology that once heard is near impossible to live without.