Out of all the boost pedals I've cycled through my 2203 over the years, Vintage OD-1's, Vintage SD-1's, Vintage MXR Dist+, Airis Savage Drive, Suhr Original 2 button Koko, Ibanez TS9, Furman PQ3, Empress Parametric EQ and a few more. All of these are really good and I lked them all to a certain extent.
The following are the pedals I like the most:
For Classic Rock to Hard Rock
SRB OD808 Boutique 808 and SD-1 in one pedal that has a three way clipping and fat switch, company closed down hard to find now
Maxon OD808, I hear the OD808X is awesome as well, even though I have the SRB I did buy the Maxon OD808 twice that's how much I liked it after I stupidly sold my first one. It just has that something you can't quite put your finger on but it has it that set it apart from my SRB OD808.
For boosting into metal and more modern territory
VFE Standout EQ pedal( I bought from Psychodave, thanks DAVE is still luv it) I actually prefer it to my Parametric EQ's,
Maxon ST9 pro plus
The Furman PQ3/PQ4 are still good but these new Master Effects PQ3 PQ4 pro pedals are something I want to try out.