#Amber on #Android can manage your keys if you want a central storage. #Amethyst plays very nicely with it and with separate identities. If you're using another app that doesn't support multiple identities, you can probably bootleg it by just removing permissions for one account and allowing it access to a different one when the client complains.

On Desktop, I think the most popular option is to use a browser extension and a web-based client like Coracle. I unfortunately don't recall the names of any extensions and don't want to get them wrong. There are a few key management extensions for Firefox, and I'm sure Chrome has its own. I'm not sure how well those web clients handle separate identities, though. Even if they don't, you can use a similar permissions trick as with Amber, just remove access to one identity and allow a different one when the client complains.