https://themeforest.net/category/forums/phpbb?srsltid=AfmBOoqo6yZkNY3CDb2_SgI5DpgANwWlqjIsrOzLvOE59fLRECkw1VI8

Some look pretty good, but, of course, the plan is to move to XenForo.

Anyway, the themes on the link seem a bit more modern, maybe being like or better than XF themes.