Although there's no definitive number for the amount of commercially-released Speccy games, 16,000 seems to be in the right ballpark. Almost as equally difficult to define, is the amount of software labels. I started these polls up this year, and we've got through 31 different brands. We are certainly not finished, not even halfway. I think there are hundreds of software brands over the Speccy's commerical era, maybe it's in the low four figures.
Anyway, I perused the final A-Z polls to derive the list of software houses we've voted on throughout 2019, which also included 'sister' brands, and this is what we have so far, chosen by YOU, the forum members...
ACE: Xecutor
Activision: Enduro Racer
Bug Byte: Manic Miner
Bulldog: Feud
Electric Dreams: R-Type
Elite: Commando
Encore: Spitfire
Entertainment USA: Ninja
Gamestar: Barry McGuigan World Championship Boxing
Hewson: Nebulus
Hit-Pak: Batty
Imagine: Target Renegade
Interceptor Software: Tales Of The Arabian Nights
Llamasoft: Headbangers Heaven
Mastertronic Added Dimension: 180
Mastertronic Plus: Gregory Loses His Clock
Mastertronic: Finders Keepers
Mastervision: Sinbad And The Golden Ship
Melbourne House: The Hobbit
Micromega: Deathchase
Microsphere: Skool Daze
Mikro-Gen: Three Weeks In Paradise
Ocean: Head Over Heels
Players Premier: Lost Caves
Players Software: Crime Busters
Rack-It: Draughts Genius
Severn Software: Jogger
Softek: Joust
Software Projects: Jet Set Willy
Spectrum Games: Monster Muncher
The Edge: Fairlight
Ultimate: Atic Atac
I will resume the polls on Sunday 5th January 2020, starting with Beyond (which will very likely be won by a certain Mike Singleton RPG from 1984), Legend and A 'n' F Software.