Did Galactic Empire have any regular troops before they adopted clones?
Wait. Stop. The Galactic Empire originally only used Jango Fett clones. They were accompanied by Human commanders as well as clone officers. After the advanced aging of the clones began to make the clones unfit for duty it was decided to integrate them with normal humans who were trained to have fanatical loyalty to the Emperor.
Yeah, but did the Empire have regular troops before they started to use clones?
Do you mean humans or non-humans?
Both
Well the Galactic Empire was formed from the remains of the Galactic Republic, so the army at the time was the Grand Army of the Republic (clones), so I'm not sure what you mean by before they started to use clones.
If you're talking about the Republic before the Empire, then they had the Judicial branch of the government which served as the peace keepers of the Republic.
To find any kind of formal military that was not the clone army, you'd have to look at the Old Republic before the Galactic Republic of the movies.