This is the beta release of a Tint2 theme I made from scratch trying to mimic the look of the Air theme from KDE Plasma 4.x (remember that?). I'm not sure I got the opacity completely right and some of the details of icon sizing/spacing may be off. If so, and anyone would like to comment, please feel free and I'll update the theme, taking your feedback into account.
Note: you MUST have the application "jgmenu" installed for this to work, as well as the font Noto Sans and the Oxygen icons in SVG format (this is a separate package on some distros!) for this theme to work. Like, at all. And if your terminal, file manager, and browser are not URxvt, PCManFM (GTK version), and Falkon respectively, it would be wise to change these in the theme file after extracting to /usr/share/tint2/ to better suit your needs. Have a look; it's well-documented and commented in there.