Look at Juniper Skyrocket. It's very slim, matures to 15 feet tall. Very neat & tidy habit

Thuja occidentalis 'Smaragd'.

Cupressus macrocarpa 'Goldcrest Wilma'.

Juniperus chinensis 'Robusta Green'. Grows to about 2-3 m tall, and 70 cm wide, dark green, and with an interesting texture.

Where do you pan to plant it? Asking for something slim makes me wonder if you plan to put it near a building.