I've been maintaining this table for a bit but I figured it might be useful to others, since every other similar thread/resource that I've found is pretty outdated. Data is mostly pulled from advertising pictures and I've tried to link to the OEM site as much as possible. If I missed a company, got something wrong or a link is outdated, let me know and I'll try to update it.
I don't care for the tension screw so I've highlighted that and other miscellaneous "improvements" where possible. However, it doesn't necessarily mean it's a bad lower (for instance, SOLGW is reputed to have very good upper/lower fitment) and your opinion may vary.
There may also be minor differences around the shape of the A2 reinforcement area that you might want to check.

                                                                                                                                                                                                                                                                                                                                                   

Manufacturer	Tension screw	Left-side shelf	Unshrouded selector journal	Notes
ADM	Yes	Unknown	No	Billet
APC	Yes	No	No
Alex Pro Fab	No	No	No
Allen Arms	Unknown	Unknown	Unknown
Anderson	No	No	No
Armory Dynamics	Yes	Yes	Yes	Threaded bolt catch pin
Bad Attitude Dept	No	No	No	Custom engraving available
Battle Arms Development	Yes	No	Yes	Threaded bolt catch and rear takedown pins
Bexar Arms	No	No	No
B. Kings	No	No	Yes	Threaded bolt catch and rear takedown pins
Centurion Arms	Yes	No	No
Civil Defense Armory	Yes	Yes	Yes
Dorchester Gun Shop	Yes	No	No	Example images on Gunbroker
DSArms	Unknown	Yes	Unknown
Expo Arms/Primary Arms	Yes	Unknown	No
Geissele	No	No	No
Griffin Armament Mk1	No	No	Yes
Griffin Armament Mk2	No	No	Yes	Custom forged ambi, integrated trigger guard
Intl Mil Co	No	No	No
KAK	Yes	No	No	Reddit thread showing FCG pocket
Lantac	Yes	No	No	Sample pic in post #15 below and here
M&M	No	Yes	Yes	Roll pin hole on both sides of front trigger guard ear. Gunbroker-only mfg seemingly
Matrix Arms	Unknown	Unknown	Yes
MSP Armory	No	No	No	Description says low shelf but picture shows M16 cut
Orchid Defense	No	No	Yes	Couldn't find mfg website
Riflegear	Yes	Unknown	No
River Rain	Yes	Yes	Yes
SOLGW	Yes	No	No
Standard Issue Armory	Yes	Unknown	Unknown	No pictures on site but shown on YouTube
Standard Manufacturing	No	No	No
Strategic Precision Defense	No	No	No
Thoroughbred Armament	No	No	No
ZRTS	Unknown	Unknown	Unknown	Threaded bolt catch pin

Bayou Gun Runner claims an M16 pocket but does not provide pictures on the website.

Example of a Colt full auto lower taken from this video
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Updated 4/29/2024

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Add this to the list.

Standard Issue Armory

That is all.

AIRBORNE!!!!!

And you can use the GhostGunner 3 to make your own:

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Added, thanks.

Will the ghost gunner do the markings as well?

Very nice!

Orchid Defense does not have worthless tension screws.  Uppers fit perfectly with no wobble whatsoever.  Perfect machining and anodizing.  Amazing.
The downside is that it's not true M16 cut.  

Below:  Orchid Defense lower with Colt upper.

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Griffin MKI (two different production runs) and MKII
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Updated Orchid Defense and Griffin Armament Mk1/Mk2.

Older DS Arms lowers only had the trigger pocket cut length to the back and no cut was on the selector detent side.

Current tech will not do the fonts used on .mil lowers.

The Orchid and Griffin lowers pictured look to have the correct pocket size, but the right side profile is incorrect.  The top of the selector journal should be shrouded.  It should not leave the top of the selector exposed on the right side of the receiver.

Added columns for the extra shelf and unshrouded selector journal. Thanks.

Lantac also manufactures M16 cut lower receivers.
Machining and anodizing is perfect.  Everything is in spec, but I don't like tension and bolt catch screws, which are provided with the receiver.

The picture below is of Lantac lower and Aero upper.  Particularly with this upper there's no up-down, side-side play, not even .001" movement, very unusual.  I've never seen anything like it.
Takedown pins slip fit.

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Added Lantac but made a note that their website shows a non-M16 cut lower. The ad pictures look like renderings to me.

Lantac website doesn't show the pocket of the receiver, and does not specify whether it's M 16 cut.
Only one retailer shows excellent pics of the receiver including the M16 cut pocket.

https://www.gandrtactical.com/Lantac-SF15-Forged-Lower-Receiver_p_3611.html

I was looking at how the thicker part of the wall extends to the safety selector rather than to the takedown pin area. I'll add the G&R link to the OP, thanks.

Anybody manufacturing any M16A1 lowers?

To the best of my knowledge, only Intl Mil Co out of everyone on this list makes true clone lowers, and you have to be patient to get one. Bad Attitude Dept. has a section for clone lowers but they're all A2 profile. They do sell unanodized tribute/clone lowers so you could get one and reprofile it, or buy an unanodized, unmarked one, reprofile it and then mark it as you please.

Or there's always the 80% route as posted above.

Add adm to the list.

Has anyone tried the Armory Dynamics lower? Any good?

Expo is shrouded.

Added ADM and updated Bad Attitude and Expo Arms.

Added Civil Defense Armory and Dorchester Gun Shop.