To provide this summary of SUs, I used only the maker's website, when possible.
Heimdal doesn't seem to work right, and only claims to monitor 20+ programs, some of which I have installed on the two computers I put Heimdal on! I uninstalled it immediately since it said there was no covered software installed on my computers. It works for Windows 7, 8.x & 10, for 32 & 64 bit apps, and Microsoft .NET Framework 4.6.1 (which it auto-installs if it's not already installed). I can only hope that the paid version is significantly better in other respects. The 3 reviews they posted on their website are all from the same place, in 2016, which doesn't impress, either. I had high hopes since it auto-updates, but the short list of supported software, and the fact that it wouldn't actually support them means it's garbage.
Patch My PC claims to offer support for "151 unique products that translate to 272 updates" (which means that of the 151 products, it supports multiple variants of some of them) of third-party programs (https://patchmypc.net/supported-products-scup-catalog), for Windows XP SP3, Vista 7, 8.x, & 10, for 32 & 64 bit apps. This is not freeware. However, at $1-2/computer, it's really cheap enough for anyone, and the $2 version automates updating.
FilePuma Update Detector, by Glary, doesn't indicate how many, or which, programs it supports, and it's for Windows XP SP3, Vista, 7 and 8.x, for 32 & 64 bit apps but not W10,. I've emailed to find out how many and where the full list is, but I saw 48 listed in the overview. I would expect, however, that it supports a lot of software. They don't accept publisher's suggestions to be added, but it is implied that they take them from users. I cannot determine if it automates updates.
Ninite offers support to download and update (automatically using bots) for 85 programs, but it's up to you to choose which ones (checkboxes on their site). I believe that when you've already got some of the programs installed, it skips them if they're up-to-date. It works for Windows XP SP3, Vista 7, 8, & 10, for 32 & 64 bit apps, and equivalent server versions. I've used it in the past to batch install programs I wanted so, as long as what you want is there, it downloads and installs them all for you. They accept suggestions for software to add. Among other features, updates are from the original websites. It handles multiple languages. Ninite is great if you're setting up a new computer because it helps simplify the process and then auto-updates, but if your computer is set-up, it's a minor inconvenience that it can't find what it supports and auto-update that.
Major Geeks News & Software Updater supports XP to 10, and I assume that means it also supports 64-bit apps, and it's small. It includes keeping you up-to-date on news on Major Geeks, although I'm not sure if that can be disabled if you're not interested. The program keeps an eye on drivers and offers to let you install Driver Agent, which is made by their partner, eSupport, that also created this app - at a discounted price. That means it may nag you to install that software, which some people dislike. It doesn't seem to automate updating, instead giving you control of what and when, which is nice for control freaks but not nice for those who lack the time and knowledge to make discerning decisions. eSupport Driver Agent: I tried going to the site with the name DriverAgent, but MalwareBytes blocked it (don't go there!). When I went to eSupport's site, it wasn't listed. I couldn't leave a comment on Major Geek as Discus wouldn't let me log in.
Update Checker redirects to FileHippo App Manager, so you'll need to update the list. It is small and gives you a list of the supported software that needs to be updated. It apparently can handle internal updates of apps, which not all updaters can, and can handle multiple languages. It supports Windows 8.1, Windows 8, Windows 7, Vista, XP, 2003 or 2000, for 32 & 64 bit apps. The application requires the Microsoft .NET Framework 4.0 client profile, which the installer will prompt and download automatically. There is no info about which software is supported, and this is a beta version, so I can't say I'm confident. I didn't see a link to ask them what they support, but screenshots showed some of the software.
Nessus by Tenable is far more than a software updater, and is neither free nor cheap. It seems to be the little sibling of their Tenable.io software, which you can upgrade to. They compare themselves with other professional-grade software that is designed for a wider range of security than just updates. If you're looking for a business solution, you might want to look at this, Patch My PC, Qualys, Rapid7, SecPod Saner Professional & SanerNow and BeyondTrust. At $2190/subscription, I'll skip it, and this is way beyond what I'm looking for. I'm not really sure why it's on the list.
SecPod Saner Personal doesn't really have much info on their website. It supports "all" Windows, Mac and Linux. The site seems to imply auto-updates, but it's not clear if that's true or even how many apps are supported, or whether 64-bit is. Pro and Now versions are for businesses, and fairly cheap, judging by SanerNow pricing of less than $3/month IF you use all modules (minimum of free if you only use the EDR module).
Adlice UCheck comes in 1 free and two paid ($17 & $44/yr versions). It auto-selects your language and includes Windows updates. The paid versions offer auto- and manual update. The free version only offers manual update, bulk update and uninstallation of programs, and the website claims that updates can be performed in as little as 2 clicks. It is for Windows XP, Vista 7, 8.x, & 10, for 32 & 64 bit apps. Most people will need the free or personal versions, and few will need the technician version, because the extras it grants just aren't useful for the average person. UCheck downloads directly from the maker's websites and has some nice security features, and supports 90+ apps (https://www.adlice.com/documentation/ucheck/documentation/#software).
SUMo (Software Update Monitor) by KC Software has earned a lot of awards, but there is very little info about it on their website. The pro version offers direct access to makers' websites, and auto-updates, and comes in multiple languages. It doesn't tell what OSes/versions are supported, whether it supports 64 bits, or how many apps are supported, nor, for that matter, much else. KC offers a lot of other apps that seem geared towards techies. Unfortunately, unless someone reliable on BC can recommend this product and give good info on it, I have to give it until then.
PC App Store by Baidu (I'm a bit nervous because of Chinese espionage) supports Windows XP-10, for 32 & 64 bit apps. It is freeware. There isn't much other info available as their website is in Chinese. It seems to have integrated updating, although I'm not clear if it's automatic, and can uninstall programs. http://baidu-pc-app-store.en.lo4d.com/
OUTDATEfighter by SPAMfighter in Denmark is available for Windows XP-10, and they also offer DRIVERfighter for Windows, and they list themselves as a Gold Microsoft Partner for application development. Software comes from the maker's sites, claims to access a database of over 1 million updates, is free and it auto-updates for you. They also offer other software for maintenance and security. https://www.spamfighter.com/OUTDATEfighter/
Carambis Software Updater's website was blocked by MalwareBytes, so I can't give you info other than not to go to their website.
Update Notifier by Cleansofts.org supports Windows XP-10 and provides direct download links. It works by building a list of programs on your computer, then accessing its database of updates to give you the links, which you download through your browser. It is free. There isn't much info, not even on how many or which apps it supports.
Avira Software Updater works on Windows 7-10, and not only updates over 150 critical apps, but drivers, too, something I didn't notice that any other program does. Both versions offer direct links to updates, but the pro version provides 1-click auto-updates, even for Windows. At $31.99, the pro version is one of the most expensive, however. This free software is also available in their Avira Free Security Suite, along with antivirus, VPN, system speedup, password manager, browser extensions and more. If I didn't already have MB3, I'd try that full package. https://www.avira.com/en/avira-software-updater
Orbit Download Manager used to have a software updater but, if it still exists, it is fraudulent and takes you to fake websites. I wouldn't recommend ODM, either, as it engages in other shady tactics.
Avast Free Antivirus sometimes includes a software updater that is pretty decent, but it doesn't have a stand-alone version. My experience with it was that I had to click on each update, and some updates would fail through that module. It's also included in their other suites. https://www.avast.com/en-us/f-software-updater
You can find more info on these on various websites, including BC.
Hopefully someone with experience can provide additional feedback on these programs, which I would love! Reviews of some of these programs are available on Lifewire.com. I hope this helps.