give prop_weighted_cube;setmodel props/metal_box - makes you a cube

fire_rocket_projectile;setmodel props_bts/rocket - makes you a rocket (zoom!)

give prop_paint_bomb;setmodel props/futbol - makes you a glass_futbol

give prop_exploding_futbol;setmodel npcs_personality_sphere_angry - makes you a black and red ball (bomb)

give prop_rocket_tripwire;setmodel props/tripwire_turret - makes you a prop_rocket_tripwire

give env_portal_laser;setmodel props/laser_emitter - makes you a laser emitter

give prop_wall_projector;setmodel props/wall_emitter - makes you a light bridge emitter

give prop_glass_futbol_spawner;setmodel props/futbol_dispenser - makes you a glass futbol spawner

give prop_floor_button;setmodel props/portal_button - makes you a floor button

prop_dynamic_create props_moon/lunar_rover.mdl;setmodel props_moon/lunar_rover - makes you a lunar rover

give prop_monster_box;setmodel npcs/monsters/monster_a - makes you a frankenturret

give npc_security_camera;setmodel props/security_camera - makes you a camera

give npc_portal_turret_floor;setmodel npcs/turret/turret - makes you a turret, and the white parts of the shells on your arm will move where you point

give prop_under_button;setmodel props_underground/underground_testchamber_button - makes you an old button

give prop_under_floor_button;setmodel props_underground/underground_floor_button - makes you an old floor button

give prop_tractor_beam;setmodel props/tractor_beam_emitter - makes you a funnel emitter

prop_dynamic_create npcs\glados\glados_wheatley_boss
setmodel npcs\glados\glados_wheatley_boss
in console.
sv_cheats needs to be set to 1