(without Esri License, no sign in Arcgis online needed)
Where to find ESRI map ?
Option 1:
google search "your city name" + "arcgis rest service"
Option 2:
Joseph Elfelt, seattle, WA creator of https://mappingsupport.com/ collect inital 1k towards 5k now arcgis rest service api endpoint over last 20+ years, you can download his list for free in PDF format here:
https://mappingsupport.com/p/surf_gis/list-federal-state-county-city-GIS-servers.pdf
How to open ESRI's map (without Esri License, no sign in Arcgis online needed)
Use free Transparentgov's map viewer to view ESRI's Arcgis REST api endpoint
Alternatively, you can use ESRI's map viewer, ESRI's classic map viewer, ESRI's web app viewer as well, click here
https://transparentgov.net/cleargov1/1740/how-to-open-esris-map-use-esris-map-viewer
Option 1.
3 panel expand system
https://transparentgov.net/json2tree/esri/server/folder2.html
Option 2.
2 panel expand system
https://transparentgov.net/json2tree/esri/server2/folder2.html
Option 3.
3 panel compact system
https://transparentgov.net/json2tree/esri/server/folder.html
Option 4.
2 panel compact system
https://transparentgov.net/json2tree/esri/server2/folder.html
Option 4. Advanced Layer
https://transparentgov.net/json2tree/esri/server2/searchLayer.html
Option 5. Simple Layer
https://transparentgov.net/json2tree/esri/server/searchLayer.html
Option 6. Advanced MapServer
https://transparentgov.net/json2tree/esri/server2/searchMapServer.html
Option 7. Simple MapServer
https://transparentgov.net/json2tree/esri/server/searchMapServer.html
How to use
https://transparentgov.net/cleargov1/1149/how-to-explore-arcgis-rest-api-endpoint-army-corps-engineers
https://transparentgov.net/cleargov1/1629/how-use-free-transparentgov-tool-see-through-any-government