Online exhibit in this context is not the same as the immersive tours. Museums typically have several web presence of specific collection themes that allow one to learn the purpose and the context of such collection. These web presence can be based on their permanent collection or a special exhibit.
Arizona State Museum
https://statemuseum.arizona.edu/online-exhibits
British Museum
https://artsandculture.google.com/partner/the-british-museum
(choose any online exhibit from this page)
Canadian Museum of History
https://www.historymuseum.ca/exhibitions/#online-exhibitions
Grand Rapids Public Museum
https://www.grpmcollections.org/
(scroll down to the Featured Galleries section or choose the Galleries menu on the top of the page)
Kelsey Museum of Archaeology, University of Michigan
https://lsa.umich.edu/kelsey/exhibitions/online-exhibitions.html
(list of various exhibits that you can choose from)
Lynn Museum
https://artsandculture.google.com/exhibit/blubber-bone-and-baleen-lynn-s-whaling-industry/AwICsJVYcI20IA
(an online exhibition exploring the whaling industry)
MASP - Museu de Arte de São Paulo Assis Chateaubriand, São Paulo, Brazil
https://artsandculture.google.com/partner/masp?hl=en
National Museum of Modern and Contemporary Art, Korea
https://artsandculture.google.com/partner/national-museum-of-modern-and-contemporary-art-korea?hl=en
National Women's History Museum
https://www.womenshistory.org/womens-history/online-exhibits
National Museum of the United States Air Force
http://www.nmusafvirtualtour.com/
Natural Museum of American History
https://americanhistory.si.edu/exhibitions/online
(pick and choose any online exhibits listed there)
Van Gogh Museum
https://artsandculture.google.com/partner/van-gogh-museum?hl=en
Valley Forge Natural Historical Park
https://www.nps.gov/museum/exhibits/valley_forge/img_gal.html
(go the Virtual Tour section and choose a location. Or check their All Image Gallery section)