Hi, I totally understand why in all the modelers we have all the Mesa, Fender, Marshall, vox etc things, they are legendary amps but sometimes i miss to have some amps more rare (at least in modelers world) which soundes unique and great too.
Here a little list of amps brand (famous and well known) that are great but not often found in modelers that i think can add value.
-Cornford (all of them, they sound so great imo and sims are very rare !)
-VHT, Fryette
-Laney (VH100R, mattias ia eklundh 
)
-Blackstar (artisan and serie one were great imo and never modeled i think)
-koch (any, also the greg combo is great !)
-Randall NB king 100
I would had Gjika that i heard about recentely here because it seems very unique and sounds incredible ! requested here: The most important and unique amp request?
I know there are plenty of more little boutique amp brands but i intentionally took well known brands that i find they deserve to be modeled more often.
Fortin are great but you need to own the plugins first also i know there is a Sunn Model T that is coming to the QC wich is great and unique !