Not sure if you're talking about cron or systemd, but cron definitely has that in /etc/cron.d where you can have arbitrary crontabs, or /etc/cron.{hourly|daily|weekly|monthly} where you can just place arbitrary scripts if you don't care exactly when they run, just the frequency.

you can organize them however you want on your system and then use symlinks to make them available.

there's also `systemctl --all list-timers` to view them.