Uploaded.net, adf.ly links, or any site that asks for a "password" after downloading. Legitimate 1.25 mods are never locked.
The official forum has a legacy section. Use the search filter with "[1.25]" to find original releases. This is the safest source, as files are scanned by moderators. euro truck simulator 2 1.25 mods download
ModLand allows you to sort by game version. Select "ETS2" and type "1.25" in the version drop-down. Warning: Ignore pop-up ads, but the download links themselves are generally safe for old versions. Uploaded