A complete "set preferences" illustration or three boxes with basic faces: a smiling one, a neutral one and a sad one, with a paper being put in the smiley one. 

Three Boxes With Reaction Faces

A video game energy bar  with a plus sign and lives.

Video Game Energy Bar

Piled Boxes

Storage Boxes

Cardboard boxes loaded on a rolling trolley.

Trolley With Boxes

A busy and overworked manager or employee surrounded by charts, graphs, and notifications.

Busy Project Manager Overwhelmed By Work

Bubbly

Youthful

Classy

Mellow

Offbeat

Abstract

Friendly

Cheerful

Funky

NeoLiving

Techno

HansenModern

Illustrations of bones