Over the years, I've had many different preamps. They have all been excellent.
1. Trace Elliot SM/SMX series rackmount. I will never not recommend these.
2. Trace Elliot V-Type rackmount. Like the Alembic F1-X, this is based on the Fender Dual Showman circuit, and has been well-regarded for 25 years since it was introduced in 1995.
3. SWR Interstellar Overdrive rackmount. I actually found myself using the solid-state side more than the tube side, but that's not because the tube side is bad. Bonus: built-in 5 W tube power amp can be used as a practice amp
4. JoeMeek VC1Qcs channel strip (rackmount). This makes an amazing bass guitar preamp, plus you get a built-in optical compressor that is fantastic.
Pedals on my list to buy/try;
1. DSM/Humboldt Simplifier Bass Station
2. Tech21NYC Q\Strip (and maybe SansAmp BDDI v2, PDDI v2, and VTBD)
3. Mesa Subway and/or Subway+
4. Fishman Platinum Pro
Others I like:
Darkglass Microtubes B7K Ultra v1 (but only clean)
SansAmp RBI and RPM rackmounts
What's on my bass pedalboard right now:
Boss AD-2 Acoustic Preamp
Boss BB-1X Bass Driver
Current amp:
Mesa Walkabout
The problem is, there are just so many great preamps out there, and I really don't need them all.
For awhile in the 2000s, I was bringing a 12-space rack to gigs, loaded with the SWR 'Stella, the Trace Elliot V-Type, and the JoeMeek VC1Qcs, and was planning on adding the SansAmp RBI to that rack. I was using those to feed an SWR Power 750 power amp (in the same rack), and it was an incredible rig. Totally overkill, of course. I had so many sounds and options at my disposal, when I really only needed one.
It made me happy to have my little preamp museum. I adored every single piece in that rack, and I honestly wish I hadn't been forced to sell them all off due to financial disaster later in life.