This is probably still in its infancy, and there would be debate about which locations are appropriate to include, apart from resourcing to do the photography etc.
I don't know that there is a definitive list nationally, but a number of state/territory national park services have each listed google trekker walks on their individual web sites.
Given that each state manages NPs separately, plus the handful of federal ones, I think it's unlikely that there will be a central location of these.
I also think it's very tourism based, with the mainly just the most popular short walks or locations etc being those more likely to have been done to date.
I found these which may help as a starting point. Format and content is variable:
ACT:
https://www.parks.act.gov.au/things-to-do/google-trekkerNSW:
https://www.nationalparks.nsw.gov.au/google-trekkerThe Blue Mountains ones seem to be missing for some reason.
QLD:
https://parks.desi.qld.gov.au/things-to-do/virtual-tours/google-street-view-trekkerSA:
https://www.parks.sa.gov.au/get-inspired/google-street-view-trekkerTAS: No definitive list in one place, but the following are available via Google Street View:
Mount Rufus circuit, Shadow Lake circuit, Dove Lake circuit, The Enchanted Walk, Fossil Cliffs
Darlington and Painted Cliffs on Maria Island
Lake St Clair and Dove Lake (aquatic view from PWS vessels)
WA:
https://exploreparks.dbca.wa.gov.au/get-inspired/visit-national-parks-homeI haven't looked at the federal NPs, locally managed; Uluru, Kakadu etc, or non-NP reserves.