There's Dusk, Amid Evil, Project Warlock, Hedon, Wrath: Aeon of Ruin, Hrot, Post Void, Cruelty Squad, Ion Fury, Nightmare Reaper, Vomitorium, and Ultrakill.
For upcoming games there are are Blood West, Postal: Brain Damaged, Supplice, Cultic, Hellscreen, Viscerafest, Gloomwood and Prodeus*.
There has also been a resurgence of quality remasters of old FPS games such as Turok (1 and 2), System Shock Enhanced Edition, Blood: Fresh Supply, and the Quake remaster which only just came out a few months ago.
These are just the ones I can think of right now, there are so many of these fucking things that they started making a boomer shooter magazine focused on only retro FPS games. I can't review all of these, but I will point out Dusk as being very, very good and my personal favourite FPS of the last few years. I haven't gotten around to playing it yet but Cruelty Squad has gotten a shitload of attention and praise as well. Some of these push the limit of 'retro FPS' and may not actually run on a toaster- 'Prodeus' especially stands out since it is a mix of retro aesthetics with modern rendering techniques, so it requires fairly high end hardware. If you're running on an actual potato, you can't go wrong with Hedon, Vomitorium, Supplice and Ion Fury since those all run on either the doom engine or the build engine. There are even more modern doom/build engine games as well, although I can't personally point at them.
The E1M1 magazines that I have are too big to properly attach to the post, I think, so I threw them on mediafire.https://www.mediafire.com/file/pty3ubm0ksblbc8/e1m1.zip/file