Plenty of pedals exist to provide a transparent (or not-so-transparent) hike to your volume, providing your amp isn’t already flat out and is equipped with sufficient headroom for them to make a difference to the dB level. The specific characteristics of the boost you want are all-important when choosing one.
The popular MXR Micro Amp is a straightforward clean boost with a single control, designed to add a preset level of gain. Seymour Duncan’s SFX-01 Pickup Booster adds flat-EQ boost in the same way, but when used first in your signal chain, can make a single-coil sound more like a humbucker.
Pedals like the Keeley Katana offer subtle gain as well as clean boost options, and overdrive pedals like the Fulltone Full-Drive 2 and Z-Vex Super-Duper 2-in-1 have more advanced boost functions to colour your solo tone. If you want to emphasise smoothness and sustain and control note attack, then you might consider a compressor instead.