I have tried several of the most common clipboard manager on Mate 19.04. After a lot of testing, only one worked (Clipman), albeit with duplicate icons in the panel.
I would therefore like to see Mate stock a clipboard manager in the applets list, that has been properly tested. KDE, Cinnamon and XFCE all ship with clipboard managers that can be added from the list of panel items. I see no reason why Mate shouldn't be able to do so as well.
In the meantime, can someone recommend a fully working cp manager for Mate?