The highest power or capacity，Thanks
D-type there aren't many players. Among the limited reviews by HKJ (or Torchy) cells which stand out are the Ansmann D 10000mAh, and the GP Recyko 5700 with what looks to be a quite high output voltage and 8000+mAh of capacity.
None of them is a champ power delivery wise (there are a lot better sub-C cells). 
The answer is always “Panasonic/Sanyo”, it just gets trickier with those sizes. I know when I rebuilt packs that I could order Sanyo F cells, wonder if they make something in D (or close to it).
If nothing made in Japan, I’d look for something from Varta. But for me they were always a resource for weird cells, not normal sizes.
Last stop is real D cells from China. And compare them. They’ve gotta be around 10,000 mAh+ or else it’s probably something else adapted to the size. Then check how they self-discharge and how much current you can pull from them.
As an example, a local battery store sells two D-cells. One is a AA inside an adapter, the other is the 10,000 mAh Powerex.
Thanks u very much， Barkuti
Well, I have these two brands of D nimh, both low-self discharge types: The Powerex Imedion and the Tenergy Centura.
I bought them several years ago, (perhaps 8 years?) to power my Fenix TK70 (it needs 3 or 4 D niMh ):
The Powerex Imedions are, IIRC, almost 3 times more expensive than the Tenergys.
At this moment, I only have the Imedions as I have thrown away the Tenergys due to its failure to take a charge. The Imedions are still taking a charge but its high IR will no longer allow it to power my TK70’s Turbo mode which requires 9 amps. I have utilized my Maha MH-C9000 (using Dcell adaptors) and iCharger 106B+ hobby charger refresh/analyze mode for several sessions and it did not improve its capacity. These nimh cells are hardly used.
My suspicion is that I have left these cells at well below .9v for a long-period of time when I have forgotten them as the newer lilo cell lights came into my collection, making them beyond bringing back to even near 90% of capacity and ampere load capacity.
The “confession” above, if you call it as that, brings me to my conclusion and suggestion to Vapcell before venturing into the niMh scene:
Better find out what Panasonic, and now Fujitsu, has in their vault their nimh chemistry formula as to why their Eneloop AA and AAA series of LSD are so durable, reliable, and while there is no Eneloop D type cell to compare with, there plenty of AA and AAA nimh competing in the market but in my observation, they are way behind in quality, durability to the Eneloops. (but not their 2450mAh types )
The really high mA D-cells (10k….claimed) seem to have a lot of the same problems as high mA AA > work fine at first, then the IR goes up fast, capacity decreases, and they become lame. They also seem to have higher self discharge, no matter what the specs claim.
There used to be some pretty good cells around 4-5kmA 10 years ago, but they seem to be gone. Radio Shack had a fine one.
FWIW, my Centura C-cells, work but are not going to hold up like Eneloops. Neither are my Soshine C-cells. Hard to impossible to get the same kind of quality as Eneloop in this size cell.
Likely vapcell Dennis can do something with regards to promoting D or C cell development, this is what Vapcell has been doing to certain extent with many other cell types and sizes. We'll see what happens, the Ni-MH market has been dormant for quite some time already and I guess there simply is a lack of demand. 
I wish someone made a high capacity protected li-ion cell the size of 3 D cells with a built in USB charger of some sort – would be great for 3D Maglites and the like.
I’ve got 3AA-to-D adapters that I use in a 2×D light to burn down moribund AA alkaleaks. Ain’t a high-strung light anyway, so I don’t really care about output.
But those adapters are just plastic and essentially 2 metal discs for contacts, so resistance should be low. I’d just use 3 eneloops or amaloops in those adapters if I had to.
Aha, another Tk70 owner! My Centura AA cells turned out to be crap but my four Centura D cells have held up okay (although they don’t get much use… in fact, hardly any nowadays).