SeaMonkey

This page will probably be flushed out with images at a later date. Right now, I just want to write it before I forget.

As of late, it seems as though the modern web browser's goal is to be less of a web browser and more of a nuisance. Constant updates, plugin breaking, "applications", UIs designed by Bozo The Clown, all of which puts the general user off.
SeaMonkey, supported by the same group that supports Firefox (Mozilla), is a promising browser that offers a very simple user interface (almost identical to that of Netscape Navigator of ages past) and doesn't feature the hacked-on cruft that other browsers feature. This makes it very promising.

There's just one problem. Well, two problems. The first is the lack of any contemporary ad blocking extensions. I'm not entirely sure if this is Mozilla's removing them from the extensions store, or if they're purely not supported, but µBlock Origin hasn't been available for a while, and as of the latest SeaMonkey release (2.49.1 as of this writing), neither is AdBlock Plus.

Fortunately, there is a solution! Download one of these files: AdBlock Plus or µBlock Origin. Extract these files and place the resulting (and possibly very confusingly named) .xpi file into the Extensions folder within SeaMonkey's installation directory (by default on 32-bit Windows, this is C:\Program Files\SeaMonkey).
Upon doing so and launching SeaMonkey, it will prompt you to install the add-on. Once you do so, it'll work! Now, how easy was that?

WARNING:
Close SeaMonkey before doing this! I'm not sure how well it would appreciate having random extensions added to it while it is running. Likewise, do not place these in your profile directly! Ignoring these two directions is at your own risk!

These files have been scanned and verified to be free of malware. You should scan them yourself, however, and see this for yourself.

Obtaining the needed XPI files yourself:

Install the add-on you want within an instance of Firefox (version 55 or older, see warning below)
Navigate to your profile folder (on Windows: "%appdata%\Mozilla\Profiles\{gibberish}\extensions")
For µBlock, it should be named something sane (uBlock0@something). For ABP, it'll be something as follows: {d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d}.xpi
Copy the file into the installation directory of SeaMonkey using the directions above

And that's it! Again, wasn't that easy?

WARNING:
At the very least, add-ons in Firefox 57 and newer are entirely incompatible with older versions of Firefox, and consequently SeaMonkey! In my tests, SeaMonkey ignored the add-on file, but you may not be quite so lucky!

The other problem with SeaMonkey is that of websites using the browser's "user agent string" to determine if it is outdated. Because SeaMonkey does not "rapid-release" like Firefox (and that's a blessing, trust me), it very quickly falls behind in the version number department.

Navigate to about: and grab the user agent string that is displayed there (it will look similar to this: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:51.0.3) Gecko/20100101 Firefox/55.0.3 SeaMonkey/2.48)
Navigate to about:config, and accept the risks
Search for "general.useragent.override". If it doesn't exist, create it (right-click, go to New, select string).
Set it to the user agent string you obtained, but change the Firefox version to that of the latest version (57.0 as of this writing)