Butchart gardens
Royal museum of British Columbia
Legislative Assembly buildings
Walk around the downtown/waterfront area
Chinatown (Victoria has the oldest one in Canada)
Hatley Castle (x men was filmed here)
Craigdarroch castle (it’s more a large Victorian mansion but still cool)
Beacon Hill park (don’t run over the peacocks in the street - seriously - they’re a traffic hazard)
There are lovely beaches in the northern parts of the island and Sunshine coast.
Grouse Mountain (in Vancouver)?!
Granted, I was there a decade or so ago, but you can just take a bus to the trailhead/cable car lower station and then take the cable car up there or just walk the trail up (not hard) and then take the cable car down.
Granted, it’s mainly interesting for people who like Nature.
Also, take the boat to cross the river.