I made a configuration to install the from configurations browser for Pharo 4.
You can install it and then choose your new icon set in settings.
You can also manual install them by:
smalltalkhubUser: ‘Pharo’ project: ‘MetaRepoForPharo40’;
ThemeIcons current: #IdeaUIThemeIcons asClass new.
“In Pharo 4, you might need to execute this”
This icon pack works also for Pharo 3
If you lost it, here a couple of screenshots: