Hi, this post mostly concerns plug 'n' plays, handhelds, TV consoles, and other bootleg consoles I can think of, especially from China, that are not dumped. I suppose I could say the MP5 devices with emulation are "undumped" but those have firmware, so those are dumped. Would mostly be a gag, I'm thinking. :P I'm not including cartridges because MAME isn't focused on undumped cartridges, to my knowledge (if I'm wrong, let me know).
Note that I am checking http://adb.arcadeitalia.net/
as I type up this list. I also keep in mind that mention of some devices, such as some of the Oplayer MGS devices or VG Pocket Max, are mentioned to be undumped (or at least word has gone around), so I won't focus on those. If I made any mistakes, let me know. Some are possibly redundant because they're just multicarts integrated into hardware, but I figured I'd mention in any case.
1) Coolbaby RS-8D -- This one has a 268-in-1 selection of games. I know that the RS-8 one is dumped, but not this one.
2) Gamewalk 20-in-1 -- Appears to be a China-exclusive device. See this link: https://engtb.com/item/taobao/678724147938.html
(but perhaps make sure to use a reliable shopping agent website)
3) MJ-1000 -- What even is this thing? Couldn't find any videos of it online. Only sold on shopee.tw, however: https://shopee.tw/product/233645059/10026422184
4) A12 handheld game -- Has 666 built-in FC games (showcased by Wicked Gamer & Collector)
5) G5 handheld game console (showcased by Wicked Gamer & Collector) . however, I found there's one with an alternate title screen of a baseball boy instead of a mouse holding a wine glass: https://archive.ph/npI68
. perhaps it's a difference with the Chinese/English language options, however?
6) GB-50 -- sold on Aliexpress
7) GB-60A -- these are also sold on Aliexpress, but the one I got has a different firmware for some reason, so it's not only the original GB-60 with just a filepath, but also the one with a more elaborate interface. There's built-in 50 games, and a few are actually VT09!
8) 400-in-1 and 200-in-1 Tech Solutions . There's the very common 400-in-1 handheld devices circulating (and I know one of the 400-in-1 was dumped online on NES Dev or so), but these two appear to have a different line-up of games on them. The latter is based on the former & was even sold at Wal-Mart, but with truncated game list probably to make the FC rom piracy less obvious (but most is still there)!
9) Some game watch, whatever this is: https://archive.ph/Pe5Sp
10) SY-888B and SY-890A . Found on Taobao listing: https://archive.ph/PnzF2
11) Some 328-in-1 handheld device? Same listing has SY-891: https://archive.ph/GqPrM
I'd say there are definitely more, but I think this is a comprehensive list for now. I used archive links for some of the Taobao listings (on superbuy) in case they go down.