@nightfall I'm no expert, but I'm always browsing tube preamps to see what's out there. Mainly looking for a truly wire balanced preamp.
From my searches on the used market here are a few suggestions.
Cary audio SLP-98 with 6SN7 tubes (many say these tubes sound great)
VTL older 2.5 (I own one built in 2013 it's a tank)
Modwright SWL 9.0 or LS100
BAT (Many versions)
Prima Luna
Audio Research (Many older versions)
My preference is the CARY or VTL, from what I have read only. I'm sure there are many users with real experience on here.