Abbreviated history of high power single cell flashlights
Warning
You may see cheap lights advertised with more lumens than these. The advertisers are making things up. If it says 900000 lumens then it’s actually a couple of hundred lumens.

Back in 2016, most single cell lights produced a maximum of 1000 lumens. CREE’s 3.5mm XP-L LED was the best you could get.
Then Nitecore release their TM03 flashlight. This was a single 18650 cell light that used CREE’s XHP70 LED and produced a groundbreaking 2800lm on turbo. The XHP70 had 4 XP-L cores in 1 package.

In 2017, Emisar released the D4. This was a small, single 18650 cell light with 4 individual XP-L LEDs, pushing out 4300lm on turbo.

In 2019, Fireflies came along and released the E07, with 7 LEDs and powered by a single 21700 cell. The went up to 6900lm using XP-L LEDs.

Later in 2019, Nightwatch released the NSX3 (specifically the NS53A version). This used 3 of CREE’s XHP50.2 LEDs. The XHP50 (and later XHP50.2) used 4 cores, this time the smaller XP-G series. The 12 cores in total produced 9900lm.

Now, Imalent have come along and put 3 of CREE’s XHP70.2 LEDs in 1 flashlight, producing 13,000lm. This is still 12 cores but this time they’re XP-L sized.

I don’t know of any quad XHP50.2 or XHP70.2 lights yet but these could hit about 17,000lm.
There’s also the new Luminus SBT90.2 LED. This is 9mm, even bigger than the XHP70.2 but can output over 5000lm (7500lm in a BLF GT90), so with enough current a quad could reach well over 20,000lm.
These impressive lumen numbers are all on the short-lived “turbo” modes though. Most of them will step down to below 1000lm after less than a minute.