List updated, May 2021.
The Tucows site has closed its doors and shipped the famous cows off to the local burger-flipping joint. In the early years of the broadband Internet the Tucows site was a go-to-place for desktop PC freeware for Windows, and well-known for its “two cows” graphic logo.
Key ongoing alternatives for users of desktop PCs and classic Windows freeware in 2021 are…
Softpedia. The usual go-to, found from a general shallow-search search-engine such as DuckDuckGo. Mixes trials with well-documented freeware, but it’s obvious which is which.
Lo4D, I rarely use it, but it’s useful if you want a second opinion on a Softpedia find.
MajorGeeks. The best for tracking freeware on a daily or weekly basis, re: what’s new or updated. Also very comprehensive, to the point of including selected trialware and shareware. Just avoid the scattered text ads for downloads of the Malwarebytes software, which is ‘limpet-ware’ — it does what it says, but is a lead-in to a purchase and I found it to be extremely difficult to remove once installed.
Filepanda.cc is a possible fallback.
OldApps is also useful if you need a specific older version. Despite the name, it’s classic Windows desktop software and not mobile apps. Here you find software from more than about five years ago, it seems. It also has some Mac pages, and useful forums.
GitHub Search can be useful, if you know what functionality you’re looking for and the precise terminology. Such as Scan Tailor Experimental 2015 for automatic de-curving of photos of opened book pages.
A final backstop is The Internet Archive Software Collection which has all sorts of golden oldies for Windows. Such as a 2020 version of the avast_free_antivirus_setup_offline.exe installer — to run on an older Windows 7 PC offline server for some special academic use. Later 2021 versions of this leading freeware anti-virus refused to install on old Windows 7 PCs. Archive.org also has ISOs of old magazine cover-CDs and DVDs. You’ll need a freeware tool to mount the ISO, such as Daemon Tools Lite or WinCDEmu. The latter can mount ISOs without needing a special driver, which can be useful on persnickety workstation PCs.
Being a bit of a connoisseur of rare or overlooked graphics and utility freeware for the Windows desktop, I also know that many nice bits of freeware never reach such sites, and reside on the maker site or some specialist software-specific directory like Paint.NET Plugins Index. Sometimes the latest updates from a solo maker are only ever posted on forum threads, with Dropbox links, and that’s the last you hear of him. In such cases, a search with a deep-search engine such as Google is often needed, as such recent or forum-buried things are usually not highly ranked by the search-engines. Yippy can also be useful for finding free scripts.
Finally, avoid sites like FileHippo, which used to be good but have turned to the dark side.
Update: Filehorse is a new major one in early summer 2021. Seems to be legit.