Highest value pre under 1.5k used?

You may have to stretch that budget to get all three.   I just bought a NIB old stock Zesto Leto preamp.  Sure it was more than I planned on spending but it was worth every penny.   I have long said the preamp is the most important component....maybe even more than the speaker you choose.   Which also is often times used with components that don't do them justice , so you upgrade speakers.  The electronics are so vital to good sound. 

Your options are better if you can do without balanced.   Quicksilver preamp with remote, have Mike wire tape out in parallel with main out so you have dual rca out.  Killer pre, brand new for $1600. 3 year warranty.  Its way better quality than most anything close in price

I have a pair of QS Mid Monos and his headphone amp.

Those amps sound so good.... they compete with much more expensive amps .   

Used I would recommend a CJ ET3 SE if you can find one reasonably 

Quicksilver excellent SE. You might find an ARC used….

ModWright SWL 9.0 SE. Not balanced. Great preamp for the money.

You can get a new Belles Aria pre for that. Warning though, I’ve had the more expensive Bells Aria Signature on order for over 3 months now, and Johnny at Audio Connection is checking on it’s status for me this week. I’m trying to be patient. You might try Johnny about the ‘standard’ Aria, heck, he might have one in stock, don’t know.

There is a used Counterpoint 3000 listed here on Agon right now. I understand a nice pre. It’s a bit over your budget though, maybe they would entertain an offer. You can find Counterpoint pre’s on the used market and know they are well regarded, but out off business now.

Good luck.