I previously wrote a quick post on using a connection manager in Linux. Link here:
I have used for the most part something called the Gnome Connection Manager. However it is poorly maintained and had a few small annoyances also.
I revisited a utility called PAC Manager (link here https://sourceforge.net/projects/pacmanager/).
So far it does pretty much everything I need as far as maintaining details for server names and SSH login information. It does have tabbed windows, organize in groups and an amazing number of customization features. It also integrates pretty nicely with KeePass to maintain passwords with.
It would be better if the main distros include this tool but it does at least have .deb and .rpm packages.
I also gave a current version of Remmina another try as it seems best maintained of the bunch but it still gave me unexpected behavior. Like a SSH window just disappearing etc.