As of late 2024, the landscape is changing. Sega and Bandai Namco have increased legal pressure on ROM sites. Furthermore, TeknoParrot v1.0 and above introduced a "Telemetry" feature that theoretically could detect pirated DLC, though it currently does not ban users.
The arcade preservation community uses a standard called "Redump." You can find (lists of checksums) that verify legitimate dumps. You would then:
Teknoparrot is a popular emulator for arcade games, and the ROMs Pack Free is a collection of game data (ROMs) that can be used with the emulator. The free pack likely contains a selection of games that can be played using the Teknoparrot emulator.
In classic emulation, a "ROM" is a read-only memory chip dump. For TeknoParrot, the files are different: