Shadowverse: Worlds Beyond resets daily at 12:00 PM PST. If you meant the older Shadowverse service, its daily reset was also reported at 12:00 noon PST.

For the main reset types:

[6] [6] [3]
Reset typeTime in PSTSource
Daily reset12:00 PM
Weekly resetSunday at 12:00 PM
Season resetLast day of the month at 6:00 PM
If you’re asking about a specific event or mode, that reset can be different from the standard daily server reset.