The link that I posted above provides a download links for all versions of Warcraft III (no Reforged), in case you don't own the Classic game just yet by the time Reforged came out on January 2020.
The "Game Installers" section has two versions: the original installers that require CDs/ISO, which installs 1.00 (ROC) and 1.07 (TFT), and the digital installers downloaded from Battle.net, which is patched up to 1.21b (the first patch that removes the CD check on both games) and 1.27a (the first patch that supports modern OS). If you download one of these versions, you can still download the patch given in the "Patch Installers" section up to 1.27b (the last patch without Battle.net Launcher). Nonetheless, a legitimate CD Keys is required and you should NOT click on "Battle.net" button upon starting the game, which obviously downloads the Battle.net Launcher (and installs the Reforged).
The "Game Files" section provides a download links for the pre-installed client between 1.28 and 1.31. These versions are pre-installed, meaning you don't need to actually install the game, unlike the ones provided in the "Game Installers". Just extract the RAR files and start the game using "Warcraft III.exe". Do not use the Launcher, as it will automatically update your game to Reforged.
If you accidentally get Reforged and you still want older patches without Reforged features, you probably need to delete everything that's related to Reforged, which includes the registries that could interfere your versions.