Found a Nectaris GB enthusiast

[ReNardier]

for when you get around to the GB KISS(id imagine that a IR USB device would help emulation for those that can't afford to get it or to try and mitigate scalping)
http://nectaris.tg-16.com/intro-nectaris-GB-KISS-LINK-FAQ-gameboy.html
the full scans of the manual seem to be missing, the insert ones though are here
http://nectaris.tg-16.com/gbim/insert1.jpg
http://nectaris.tg-16.com/gbim/insert2.jpg
you could try and contact him to see if he still has the manual scans, but i don't know how much luck you'll have
the passion he displayed reminded me of you

[ReNardier]

and just because i guess ill post a list of accessories from the ds accessories wikipedia page wich im quite sure you know all of them already:
Nintendo DS Digital TV Tuner, DS Direction Sensing Card,
DS Direction Sensing Card, Beypoint Reader, Piano Keyboard,
Ranger GPS System, Hyperkin 3 Game Selector, Dragon NDS Lite FM Radio Converter,
FM Radio by Futureronics, The Bling Tunes FM Radio, Cyber Famulator Lite,
Hoshizora Navi
why did i do that?, well because AND due to the last one not being on the wiki meaning it might be new to you, on this link you'll see what the cart does
https://gamefaqs.gamespot.com/top10/2745-the-top-10-nintendo-gameboy-generation-cartridges-with-built
plus i did find some videos on the bayer didget
https://www.youtube.com/watch?v=xctzgFfMEJg
https://www.youtube.com/watch?v=kYS2QkqbLb0
http://thisiscaleb.wordpress.com/2010/06/01/bayers-didget%E2%84%A2-review-by-caleb/
i think the mother could be contacted, but i don't know if after 12 years they still have the didget
https://www.ydmv.net/2010/05/bayer-didget-first-look.html
https://ladyandtheblog.com/didget-bayers-diabetes-care-system/
https://vgcollect.com/item/63398 a collector has it
it quite likely will lead to nothing, but still

[ReNardier]

found some more things
http://www.eagb.net/advance/hr30.html
http://www.gameboy-advance.net/accessories/gba_interactive_digital_camera.htm
and sorry if the didget stuff seemed weird, its just that i decided to search and found some stuff, quite likely it isn't useful to you so again, sorry

[shonumi]

Thanks for posting all of that information! I actually referenced that Nectaris site quite a bit while writing my upcoming book. It's a shame some of the pictures of the GB KISS LINK are so low-resolution though.

I still have my eye on quite a few DS accessories to work on. I've had most of the items on that list in my possession for a while (including the NTR-030, e.g. Hoshizora Navi). Still looking for the Bayer Digit though. Unfortunately, the DS is going to have to wait until I finish up with the rest of the GBA stuff. We're actually very close to having all of the officially licensed DMG/GBC/GBA accessories/peripherals/cartridges emulated in some form or another, so I want to see that goal taken care of first before doing more DS work. Unlicensed products aren't a priority at this time either, although I have my eye on them (such as the Shark MX, for instance).

Regardless, I appreciate your enthusiasm for exotic Game Boy/DS hardware! Feel free to post any more research you come across here. It's a slow process, but we're gradually preserving things.

[upintheairsheep]

Thank you for showing enthusiasm in obscure accessories too!

[upintheairsheep]

I also am excited in emulating or at least virtualizing (making a full Linux VM) for old Smart TVs.

[upintheairsheep]

https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.ebay.com%2Fp%2F1700101311&psig=AOvVaw16kNDTsILRrpUP2k9ugDRi&ust=1676134375905000&source=images&cd=vfe&ved=0CA0QjhxqFwoTCNjcpKS1i_0CFQAAAAAdAAAAABAf