The Internet Archive hosts No-Intro and Redump sets, which are verified, clean dumps of 3DS game carts. You will find base games and separate update packs.
Assuming you have custom firmware (Luma3DS + Boot9Strap), you will need a CIA installer. The most popular is . download 3ds cia files upd
The Ultimate Guide to 3DS CIA Files and Updates The Nintendo 3DS homebrew and custom firmware (CFW) community remains incredibly active. For enthusiasts looking to back up their physical game cartridges, play translated titles, or enjoy homebrew software, understanding how to handle and install is an essential skill. The Internet Archive hosts No-Intro and Redump sets,