Random thoughts outside of the really big hits -
Dwight Yoakam songs like Ain't That lonely yet, 1000 miles from nowhere, etc.
Does Butterfly Kisses count?
Brad Paisley's whole first album is really good. I think it was 1999.
Old Toby Keith before he got so onery - stuff like who's that man, shoulda been a cowboy, etc.
Clint Black - like the Rain is good
Going through the Big D and I don't mean dallas - but forgot who sings it
I really like Allison Kraus - one of my favorite voices ever. But that may have been early 2000s
Trashy Women by Confederate Railroad
Montgomery Gentry - Hillbilly Shoes and Daddy won't sell the farm are right around that 1999-2000 range
And of course, anything with George Strait