From what system is this cartridge? Its a little smaller than a Game Boy DMG cart.
It kinda looks like a game king cartridge, from the inside bits (can’t find a pic of the whole thing), but that’s from the early 2000s. I went through a list of older handhelds and that’s the closest entry. But importantly, that probably isn’t it.
What you have is probably a regional knock-off sort of thing, or something that was never popular/prominent enough to be added to the wiki page.
This is the handheld list I went through. I stopped at the DS, as I assume yours is considerably older than that. Some of the old systems only have a handful of games for them, so it’s possible it’s something that just wasn’t made in large numbers, but my bet is on super-generic-knockoff-gamebay/gamboy/toyboy/gamekid handheld system (jokey knockoff names not real things afaik), which are not listed with the actual non-knockoff systems. (I wasn’t able to find much about vintage knockoff/copy systems)
https://en.m.wikipedia.org/wiki/List_of_handheld_game_consoles
