I know Paper Theme is not targeted at GTK2 but in fact it works very well with GTK2 in MATE Desktop.
The only annoying thing is that menus are not delimited and they have the same background color than Caja (Nautilus fork) windows or even LibreOffice pages so they are not pleasing to use.
Ubuntu 16.04 / MATE Desktop 1.16 / GTK2 / paper-gtk-theme 2.1+r265~daily~ubuntu16.04.1
I know Paper Theme is not targeted at GTK2 but in fact it works very well with GTK2 in MATE Desktop. The only annoying thing is that menus are not delimited and they have the same background color than Caja (Nautilus fork) windows or even LibreOffice pages so they are not pleasing to use.
