Not strictly a pedal, but I bought a (nearly new) Cioks DC7 power supply, and it has been a revelation. I was previously using a Caline power supply, which was noisy and unreliable. It couldn't manage all my power needs.
Runner up is a Laney Digbeth DB-pre. It sounds good to my ears and the built in headphones out is great for practice when traveling.
TL;DR Cioks DC7 expensive but amazing power supply
Laney Digbeth DB-pre good cheap DI/preamp.